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.
67026 vulnerabilities reference this CWE, most recent first.
GHSA-X7HR-W5R2-H6WG
Vulnerability from github – Published: 2025-03-03 09:30 – Updated: 2025-06-30 12:51Prism (aka PrismJS) through 1.29.0 allows DOM Clobbering (with resultant XSS for untrusted input that contains HTML but does not directly contain JavaScript), because document.currentScript lookup can be shadowed by attacker-injected HTML elements.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "prismjs"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.30.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-53382"
],
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-94"
],
"github_reviewed": true,
"github_reviewed_at": "2025-03-03T20:16:32Z",
"nvd_published_at": "2025-03-03T07:15:33Z",
"severity": "MODERATE"
},
"details": "Prism (aka PrismJS) through 1.29.0 allows DOM Clobbering (with resultant XSS for untrusted input that contains HTML but does not directly contain JavaScript), because document.currentScript lookup can be shadowed by attacker-injected HTML elements.",
"id": "GHSA-x7hr-w5r2-h6wg",
"modified": "2025-06-30T12:51:19Z",
"published": "2025-03-03T09:30:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-53382"
},
{
"type": "WEB",
"url": "https://github.com/PrismJS/prism/pull/3863"
},
{
"type": "WEB",
"url": "https://github.com/PrismJS/prism/commit/8e8b9352dac64457194dd9e51096b4772532e53d"
},
{
"type": "WEB",
"url": "https://gist.github.com/jackfromeast/aeb128e44f05f95828a1a824708df660"
},
{
"type": "PACKAGE",
"url": "https://github.com/PrismJS/prism"
},
{
"type": "WEB",
"url": "https://github.com/PrismJS/prism/blob/59e5a3471377057de1f401ba38337aca27b80e03/prism.js#L226-L259"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "PrismJS DOM Clobbering vulnerability"
}
GHSA-X7HV-G5WJ-P26V
Vulnerability from github – Published: 2022-05-24 17:46 – Updated: 2022-05-24 17:46Magnolia CMS contains a stored cross-site scripting (XSS) vulnerability in the /magnoliaPublic/travel/members/login.html mgnlUserId parameter.
{
"affected": [],
"aliases": [
"CVE-2021-25894"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-04-02T12:15:00Z",
"severity": "MODERATE"
},
"details": "Magnolia CMS contains a stored cross-site scripting (XSS) vulnerability in the /magnoliaPublic/travel/members/login.html mgnlUserId parameter.",
"id": "GHSA-x7hv-g5wj-p26v",
"modified": "2022-05-24T17:46:26Z",
"published": "2022-05-24T17:46:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-25894"
},
{
"type": "WEB",
"url": "https://git.magnolia-cms.com/projects/MODULES/repos/public-user-registration/commits/80c096c24d39ba2050b778e68ef838d79d4811dc"
},
{
"type": "WEB",
"url": "https://www.itas.vn/itas-security-team-found-multi-vulnerabilities-on-magnolia-cms-platform"
},
{
"type": "WEB",
"url": "https://www.magnolia-cms.com"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-X7HW-JWRW-QW78
Vulnerability from github – Published: 2024-03-14 06:32 – Updated: 2025-03-27 18:30Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in the SonicOS SSLVPN portal allows a remote authenticated attacker as a firewall 'admin' user to store and execute arbitrary JavaScript code.
{
"affected": [],
"aliases": [
"CVE-2024-22397"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-03-14T04:15:09Z",
"severity": "HIGH"
},
"details": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027) in the SonicOS SSLVPN portal allows a remote authenticated attacker as a firewall \u0027admin\u0027 user to store and execute arbitrary JavaScript code.",
"id": "GHSA-x7hw-jwrw-qw78",
"modified": "2025-03-27T18:30:38Z",
"published": "2024-03-14T06:32:00Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-22397"
},
{
"type": "WEB",
"url": "https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2024-0005"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-X7J5-2QJW-2RRX
Vulnerability from github – Published: 2022-11-04 12:00 – Updated: 2026-04-28 21:32Auth. (admin+) Stored Cross-Site Scripting (XSS) vulnerability in JumpDEMAND Inc. 4ECPS Web Forms plugin <= 0.2.17 on WordPress.
{
"affected": [],
"aliases": [
"CVE-2022-44628"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-11-03T20:15:00Z",
"severity": "MODERATE"
},
"details": "Auth. (admin+) Stored Cross-Site Scripting (XSS) vulnerability in JumpDEMAND Inc. 4ECPS Web Forms plugin \u003c= 0.2.17 on WordPress.",
"id": "GHSA-x7j5-2qjw-2rrx",
"modified": "2026-04-28T21:32:52Z",
"published": "2022-11-04T12:00:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-44628"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/vulnerability/4ecps-webforms/wordpress-4ecps-web-forms-plugin-0-2-17-auth-stored-cross-site-scripting-xss-vulnerability?_s_id=cve"
},
{
"type": "WEB",
"url": "https://wordpress.org/plugins/4ecps-webforms"
}
],
"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-X7J5-3P38-F69M
Vulnerability from github – Published: 2024-03-28 21:30 – Updated: 2024-08-20 21:30Cross Site Scripting vulnerability in Insurance Mangement System v.1.0.0 and before allows a remote attacker to execute arbitrary code via the Email input field.
{
"affected": [],
"aliases": [
"CVE-2024-31063"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-03-28T19:15:49Z",
"severity": "MODERATE"
},
"details": "Cross Site Scripting vulnerability in Insurance Mangement System v.1.0.0 and before allows a remote attacker to execute arbitrary code via the Email input field.",
"id": "GHSA-x7j5-3p38-f69m",
"modified": "2024-08-20T21:30:30Z",
"published": "2024-03-28T21:30:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-31063"
},
{
"type": "WEB",
"url": "https://github.com/sahildari/cve/blob/master/CVE-2024-31063.md"
},
{
"type": "WEB",
"url": "https://owasp.org/www-community/attacks/xss"
},
{
"type": "WEB",
"url": "https://portswigger.net/web-security/cross-site-scripting/stored"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-X7J7-QP7J-HW3Q
Vulnerability from github – Published: 2021-11-16 17:04 – Updated: 2021-11-16 15:46Impact
Kirby's writer field stores its formatted content as HTML code. Unlike with other field types, it is not possible to escape HTML special characters against cross-site scripting (XSS) attacks, otherwise the formatting would be lost.
Cross-site scripting (XSS) is a type of vulnerability that allows to execute any kind of JavaScript code inside the site frontend or Panel session of other users. If the user is logged in to the Panel, a harmful script can for example trigger requests to Kirby's API with the permissions of the victim.
Because the writer field did not securely sanitize its contents on save, it was possible to inject malicious HTML code into the content file by sending it to Kirby's API directly without using the Panel. This malicious HTML code would then be displayed on the site frontend and executed in the browsers of site visitors and logged in users who are browsing the site.
This vulnerability is critical if you might have potential attackers in your group of authenticated Panel users. They can escalate their privileges if they get access to the Panel session of an admin user. Depending on your site, other JavaScript-powered attacks are possible.
You are not affected if you don't use the writer field in any of your blueprints. The attack can only be performed by logged-in users and only surfaces in the site frontend (i.e. in your templates). The Panel itself is unaffected and will not execute JavaScript that was injected into writer field content.
Patches
We have patched the vulnerability in Kirby 3.5.8 by sanitizing all writer field contents on the backend whenever the content is modified via Kirby's API. Please update to this or a later version to fix the vulnerability.
Credits
Thanks to Azrul Ikhwan Zulkifli (@azrultech) from BAE Systems AI Vulnerability Research Team for responsibly reporting the identified issue.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "getkirby/cms"
},
"ranges": [
{
"events": [
{
"introduced": "3.5.0"
},
{
"fixed": "3.5.8"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2021-41252"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2021-11-16T15:46:57Z",
"nvd_published_at": "2021-11-16T18:15:00Z",
"severity": "MODERATE"
},
"details": "### Impact\n\nKirby\u0027s [writer field](https://getkirby.com/docs/reference/panel/fields/writer) stores its formatted content as HTML code. Unlike with other field types, it is not possible to [escape HTML special characters](https://getkirby.com/docs/guide/templates/escaping) against cross-site scripting (XSS) attacks, otherwise the formatting would be lost.\n\nCross-site scripting (XSS) is a type of vulnerability that allows to execute any kind of JavaScript code inside the site frontend or Panel session of other users. If the user is logged in to the Panel, a harmful script can for example trigger requests to Kirby\u0027s API with the permissions of the victim.\n\nBecause the writer field did not securely sanitize its contents on save, it was possible to inject malicious HTML code into the content file by sending it to Kirby\u0027s API directly without using the Panel. This malicious HTML code would then be displayed on the site frontend and executed in the browsers of site visitors and logged in users who are browsing the site.\n\nThis vulnerability is critical if you might have potential attackers in your group of authenticated Panel users. They can escalate their privileges if they get access to the Panel session of an admin user. Depending on your site, other JavaScript-powered attacks are possible.\n\nYou are *not* affected if you don\u0027t use the writer field in any of your blueprints. The attack can only be performed by logged-in users and only surfaces in the site frontend (i.e. in your templates). The Panel itself is unaffected and will not execute JavaScript that was injected into writer field content.\n\n### Patches\n\nWe have patched the vulnerability in [Kirby 3.5.8](https://github.com/getkirby/kirby/releases/tag/3.5.8) by sanitizing all writer field contents on the backend whenever the content is modified via Kirby\u0027s API. Please update to this or a [later version](https://github.com/getkirby/kirby/releases/) to fix the vulnerability.\n\n### Credits\n\nThanks to Azrul Ikhwan Zulkifli (@azrultech) from BAE Systems AI Vulnerability Research Team for responsibly reporting the identified issue.",
"id": "GHSA-x7j7-qp7j-hw3q",
"modified": "2021-11-16T15:46:57Z",
"published": "2021-11-16T17:04:19Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/getkirby/kirby/security/advisories/GHSA-x7j7-qp7j-hw3q"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-41252"
},
{
"type": "WEB",
"url": "https://github.com/getkirby/kirby/commit/25fc5c6b330442e6433c99befc688f3698c5d1fc"
},
{
"type": "PACKAGE",
"url": "https://github.com/getkirby/kirby"
},
{
"type": "WEB",
"url": "https://github.com/getkirby/kirby/releases/tag/3.5.8"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "Cross-site scripting (XSS) from writer field content in the site frontend"
}
GHSA-X7J8-JPRM-X8F3
Vulnerability from github – Published: 2022-05-14 03:41 – Updated: 2022-05-14 03:41Multiple cross-site scripting (XSS) vulnerabilities in Fortinet FortiGate UTM WAF appliances with FortiOS 4.3.x before 4.3.6 allow remote attackers to inject arbitrary web script or HTML via vectors involving the (1) Endpoint Monitor, (2) Dialup List, or (3) Log&Report Display modules, or the fields_sorted_opt parameter to (4) user/auth/list or (5) endpointcompliance/app_detect/predefined_sig_list.
{
"affected": [],
"aliases": [
"CVE-2012-0941"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-02-08T23:29:00Z",
"severity": "MODERATE"
},
"details": "Multiple cross-site scripting (XSS) vulnerabilities in Fortinet FortiGate UTM WAF appliances with FortiOS 4.3.x before 4.3.6 allow remote attackers to inject arbitrary web script or HTML via vectors involving the (1) Endpoint Monitor, (2) Dialup List, or (3) Log\u0026Report Display modules, or the fields_sorted_opt parameter to (4) user/auth/list or (5) endpointcompliance/app_detect/predefined_sig_list.",
"id": "GHSA-x7j8-jprm-x8f3",
"modified": "2022-05-14T03:41:29Z",
"published": "2022-05-14T03:41:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2012-0941"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/72761"
},
{
"type": "WEB",
"url": "https://fortiguard.com/psirt/FG-IR-012-001"
},
{
"type": "WEB",
"url": "https://securitytracker.com/id/1026594"
},
{
"type": "WEB",
"url": "https://www.vulnerability-lab.com/get_content.php?id=144"
},
{
"type": "WEB",
"url": "http://packetstormsecurity.org/files/109168/VL-144.txt"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/51708"
}
],
"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-X7JX-72G4-98CW
Vulnerability from github – Published: 2025-09-05 18:31 – Updated: 2026-04-01 18:36Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Vincent Boiardt Easy Flash Embed allows Stored XSS. This issue affects Easy Flash Embed: from n/a through 1.0.
{
"affected": [],
"aliases": [
"CVE-2025-48105"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-05T17:15:36Z",
"severity": "MODERATE"
},
"details": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027) vulnerability in Vincent Boiardt Easy Flash Embed allows Stored XSS. This issue affects Easy Flash Embed: from n/a through 1.0.",
"id": "GHSA-x7jx-72g4-98cw",
"modified": "2026-04-01T18:36:07Z",
"published": "2025-09-05T18:31:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-48105"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/wordpress/plugin/easy-flash-embed/vulnerability/wordpress-easy-flash-embed-plugin-1-0-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-X7MF-WRH9-R76C
Vulnerability from github – Published: 2024-03-18 20:29 – Updated: 2025-01-21 18:13Impact
OctoPrint versions up until and including 1.9.3 contain a vulnerability that allows malicious admins to configure or talk a victim with administrator rights into configuring a webcam snapshot URL which when tested through the "Test" button included in the web interface will execute JavaScript code in the victims browser when attempting to render the snapshot image.
An attacker who successfully talked a victim with admin rights into performing a snapshot test with such a crafted URL could use this to retrieve or modify sensitive configuration settings, interrupt prints or otherwise interact with the OctoPrint instance in a malicious way.
Patches
The vulnerability will be patched in version 1.10.0.
Workaround
OctoPrint administrators are strongly advised to thoroughly vet who has admin access to their installation and what settings they modify based on instructions by strangers.
PoC
Below are the steps to reproduce the vulnerability:
- Create a URL that responds with a malicious content type. For example, creating the following python script: ``` from http.server import BaseHTTPRequestHandler, HTTPServer
class MyHTTPRequestHandler(BaseHTTPRequestHandler): def do_GET(self): self.send_response(200) self.send_header('Content-Type', 'image/"onerror="alert(1)"') self.end_headers() self.wfile.write(b'Ok')
def run(): server_address = ('', 8080) httpd = HTTPServer(server_address, MyHTTPRequestHandler) print('Server listening on 0.0.0.0:8080...') httpd.serve_forever()
if name == 'main': run() ```
-
Go to OctoPrint settings --> Plugins --> Classic Webcam and enter the URL of that page as the Snapshot URL.
-
Click on the "Test" button to trigger XSS. A Javascript alert should appear, demonstrating the actual code injection.
Credits
This vulnerability was discovered and responsibly disclosed to OctoPrint by Jacopo Tediosi.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.9.3"
},
"package": {
"ecosystem": "PyPI",
"name": "OctoPrint"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.10.0rc3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-28237"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2024-03-18T20:29:45Z",
"nvd_published_at": "2024-03-18T22:15:07Z",
"severity": "MODERATE"
},
"details": "### Impact\n\nOctoPrint versions up until and including 1.9.3 contain a vulnerability that allows malicious admins to configure or talk a victim with administrator rights into configuring a webcam snapshot URL which when tested through the \"Test\" button included in the web interface will execute JavaScript code in the victims browser when attempting to render the snapshot image.\n\nAn attacker who successfully talked a victim with admin rights into performing a snapshot test with such a crafted URL could use this to retrieve or modify sensitive configuration settings, interrupt prints or otherwise interact with the OctoPrint instance in a malicious way.\n\n### Patches\n\nThe vulnerability will be patched in version 1.10.0.\n\n### Workaround\n\nOctoPrint administrators are strongly advised to thoroughly vet who has admin access to their installation and what settings they modify based on instructions by strangers.\n\n### PoC\n\nBelow are the steps to reproduce the vulnerability:\n\n1. Create a URL that responds with a malicious content type. For example, creating the following python script:\n ```\n from http.server import BaseHTTPRequestHandler, HTTPServer\n\n class MyHTTPRequestHandler(BaseHTTPRequestHandler):\n def do_GET(self):\n self.send_response(200)\n self.send_header(\u0027Content-Type\u0027, \u0027image/\"onerror=\"alert(1)\"\u0027)\n self.end_headers()\n self.wfile.write(b\u0027Ok\u0027)\n\n def run():\n server_address = (\u0027\u0027, 8080)\n httpd = HTTPServer(server_address, MyHTTPRequestHandler)\n print(\u0027Server listening on 0.0.0.0:8080...\u0027)\n httpd.serve_forever()\n\n if __name__ == \u0027__main__\u0027:\n run()\n ```\n\n2. Go to OctoPrint settings --\u003e Plugins --\u003e Classic Webcam and enter the URL of that page as the Snapshot URL. \n\n3. Click on the \"Test\" button to trigger XSS. A Javascript alert should appear, demonstrating the actual code injection.\n\n### Credits\n\nThis vulnerability was discovered and responsibly disclosed to OctoPrint by Jacopo Tediosi.",
"id": "GHSA-x7mf-wrh9-r76c",
"modified": "2025-01-21T18:13:00Z",
"published": "2024-03-18T20:29:45Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/OctoPrint/OctoPrint/security/advisories/GHSA-x7mf-wrh9-r76c"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-28237"
},
{
"type": "WEB",
"url": "https://github.com/OctoPrint/OctoPrint/commit/779894c1bc6478332d14bc9ed1006df1354eb517"
},
{
"type": "PACKAGE",
"url": "https://github.com/OctoPrint/OctoPrint"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/octoprint/PYSEC-2024-179.yaml"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "XSS via the \"Snapshot Test\" feature in Classic Webcam plugin settings"
}
GHSA-X7MM-9VVV-64W8
Vulnerability from github – Published: 2026-04-10 22:09 – Updated: 2026-04-10 22:09Summary
createStreamableHead({ streamKey }) interpolated its streamKey argument directly into the streaming SSR bootstrap and suspense-chunk inline scripts without identifier validation or escaping. If an application forwards untrusted data into that configuration value, the rendered scripts become a script-injection sink.
Details
streamKey was embedded into JavaScript source via dot notation in two public helpers:
createBootstrapScript()returned<script>window.${streamKey}={...}</script>renderSSRHeadSuspenseChunk()returnedwindow.${streamKey}.push(...)
No escaping, quoting, or identifier validation was applied before these strings were embedded into HTML. A streamKey such as __unhead__;globalThis.PWNED=1;// broke out of the intended property access and injected arbitrary JavaScript into the page. The JSON escaping used for streamed head entries did not protect streamKey because streamKey was inserted as raw code rather than as serialized data.
Impact
streamKey is a developer-chosen configuration value rather than a data field — the intended usage is a hardcoded identifier-shaped constant (default __unhead__). Exploitation therefore requires an application to explicitly route untrusted input into a configuration sink, which is not a documented or recommended pattern. We have no reports of any downstream project sourcing streamKey from request data.
Applications using the default streamKey, or any hardcoded custom key, are not affected.
PoC
import { createStreamableHead, renderSSRHeadShell } from 'unhead/stream/server'
const { head } = createStreamableHead({
streamKey: '__unhead__;globalThis.PWNED=1;//',
})
const html = renderSSRHeadShell(
head,
'<!doctype html><html><head></head><body></body></html>',
)
// <!doctype html><html><head><script>window.__unhead__;globalThis.PWNED=1;//={_q:[],push(e){this._q.push(e)}}</script>…
Patch
Fixed on main in 64b5ac0. The fix will ship in the next patch release of unhead.
streamKey is now validated against a conservative ASCII JavaScript-identifier pattern (/^[$_a-z][$\w]*$/i) at every sink — createStreamableHead, createBootstrapScript, and the internal stream-key resolver. Invalid values throw immediately instead of being emitted into script output.
Workarounds
Do not pass untrusted data into createStreamableHead({ streamKey }) or createBootstrapScript(key). If per-tenant keys are required, whitelist them against an identifier-safe pattern before constructing the head instance.
Credit
Thanks to @Jvr2022 for the report.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 3.0.0"
},
"package": {
"ecosystem": "npm",
"name": "unhead"
},
"ranges": [
{
"events": [
{
"introduced": "3.0.0-beta.5"
},
{
"fixed": "3.0.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2026-04-10T22:09:39Z",
"nvd_published_at": null,
"severity": "LOW"
},
"details": "### Summary\n\n`createStreamableHead({ streamKey })` interpolated its `streamKey` argument directly into the streaming SSR bootstrap and suspense-chunk inline scripts without identifier validation or escaping. If an application forwards untrusted data into that configuration value, the rendered scripts become a script-injection sink.\n\n### Details\n\n`streamKey` was embedded into JavaScript source via dot notation in two public helpers:\n\n* `createBootstrapScript()` returned `\u003cscript\u003ewindow.${streamKey}={...}\u003c/script\u003e`\n* `renderSSRHeadSuspenseChunk()` returned `window.${streamKey}.push(...)`\n\nNo escaping, quoting, or identifier validation was applied before these strings were embedded into HTML. A `streamKey` such as `__unhead__;globalThis.PWNED=1;//` broke out of the intended property access and injected arbitrary JavaScript into the page. The JSON escaping used for streamed head entries did not protect `streamKey` because `streamKey` was inserted as raw code rather than as serialized data.\n\n### Impact\n\n`streamKey` is a developer-chosen configuration value rather than a data field \u2014 the intended usage is a hardcoded identifier-shaped constant (default `__unhead__`). Exploitation therefore requires an application to explicitly route untrusted input into a configuration sink, which is not a documented or recommended pattern. We have no reports of any downstream project sourcing `streamKey` from request data.\n\nApplications using the default `streamKey`, or any hardcoded custom key, are **not affected**.\n\n### PoC\n\n```ts\nimport { createStreamableHead, renderSSRHeadShell } from \u0027unhead/stream/server\u0027\n\nconst { head } = createStreamableHead({\n streamKey: \u0027__unhead__;globalThis.PWNED=1;//\u0027,\n})\n\nconst html = renderSSRHeadShell(\n head,\n \u0027\u003c!doctype html\u003e\u003chtml\u003e\u003chead\u003e\u003c/head\u003e\u003cbody\u003e\u003c/body\u003e\u003c/html\u003e\u0027,\n)\n\n// \u003c!doctype html\u003e\u003chtml\u003e\u003chead\u003e\u003cscript\u003ewindow.__unhead__;globalThis.PWNED=1;//={_q:[],push(e){this._q.push(e)}}\u003c/script\u003e\u2026\n```\n\n### Patch\n\nFixed on `main` in [`64b5ac0`](https://github.com/unjs/unhead/commit/64b5ac0aa30cc256ea6677ce3dc4f132f81b2ff6). The fix will ship in the next patch release of `unhead`.\n\n`streamKey` is now validated against a conservative ASCII JavaScript-identifier pattern (`/^[$_a-z][$\\w]*$/i`) at every sink \u2014 `createStreamableHead`, `createBootstrapScript`, and the internal stream-key resolver. Invalid values throw immediately instead of being emitted into script output.\n\n### Workarounds\n\nDo not pass untrusted data into `createStreamableHead({ streamKey })` or `createBootstrapScript(key)`. If per-tenant keys are required, whitelist them against an identifier-safe pattern before constructing the head instance.\n\n### Credit\n\nThanks to @Jvr2022 for the report.",
"id": "GHSA-x7mm-9vvv-64w8",
"modified": "2026-04-10T22:09:39Z",
"published": "2026-04-10T22:09:39Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/unjs/unhead/security/advisories/GHSA-x7mm-9vvv-64w8"
},
{
"type": "WEB",
"url": "https://github.com/unjs/unhead/commit/64b5ac0aa30cc256ea6677ce3dc4f132f81b2ff6"
},
{
"type": "PACKAGE",
"url": "https://github.com/unjs/unhead"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "unhead: Streaming SSR `streamKey` injected into inline script without identifier validation"
}
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.