Which versions of HAX CMS are affected by CVE-2026-46496?

HAX CMS (npm packages @haxtheweb/haxcms-nodejs and @haxtheweb/video-player versions 25.0.0 and earlier) contains a stored cross-site scripting vulnerability that enables any authenticated user to…. A patch is available.

How to fix or mitigate CVE-2026-46496?

Within 24 hours: Inventory all systems using @haxtheweb/haxcms-nodejs or @haxtheweb/video-player and identify which versions are deployed; notify affected application owners. Within 7 days: Upgrade both packages to versions > 25.0.0 and deploy across all affected environments. Within 30 days: Audit application logs and database records for injected video-player elements with javascript: URIs created since package deployment; flag and investigate any malicious content; verify no unauthorized sessions remain active from before the patch.

HAX CMS CVE-2026-46496

Q: What is the CVSS score of CVE-2026-46496?

CVE-2026-46496 has a CVSS 4.0 base score of 9.3 (Critical). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/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. EPSS exploitation probability: 0.0%.

EUVD-2026-34892 CRITICAL

Cross-site Scripting (XSS) (CWE-79)

2026-05-19 https://github.com/haxtheweb/issues

GHSA-2m6p-hm3w-6jm3

Information Disclosure XSS

9.3

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

9.3 CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Scope

Lifecycle Timeline

Analysis Updated

Jun 05, 2026 - 19:30 vuln.today

v3 (cvss_changed)

Analysis Updated

Jun 05, 2026 - 19:30 vuln.today

v2 (cvss_changed)

Re-analysis Queued

Jun 05, 2026 - 19:22 vuln.today

cvss_changed

CVSS changed

Jun 05, 2026 - 19:22 NVD

9.3 (CRITICAL)

Source Code Evidence Fetched

May 19, 2026 - 15:33 vuln.today

Analysis Generated

May 19, 2026 - 15:33 vuln.today

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

24 npm packages depend on @haxtheweb/video-player (6 direct, 18 indirect)

Ecosystem-wide dependent count for version 26.0.0.

DescriptionGitHub Advisory

Summary

A stored cross-site scripting (XSS) vulnerability exists in HAX CMS due to improper sanitization of the <video-player> component.

The component allows javascript: URIs in the source attribute, which are executed when the page is viewed. This enables attackers to execute arbitrary JavaScript in the context of the victim’s browser and access sensitive data such as JWT tokens and more.

Details

The vulnerability is present in the <video-player> web component used within the HAX CMS editor.

The application fails to validate or sanitize user-supplied input in the following attributes:

source
source-data

These attributes accept arbitrary URI schemes, including javascript:, which leads to execution of attacker-controlled JavaScript in the browser.

Example vulnerable usage:

html

<video-player
  source="javascript:alert(document.domain)"
  source-type="external">
</video-player>

Because this content is stored and rendered to other users, the vulnerability is classified as a stored XSS.

The root cause is the lack of URI scheme validation and improper sanitization of component attributes before rendering. Because this content is stored and rendered to other users, the vulnerability is classified as a stored XSS.

The root cause is the lack of URI scheme validation and improper sanitization of component attributes before rendering.

PoC

Steps to reproduce:

Log in to HAX CMS as user.
Create a website or any page and switch to the HTML source editor (<>).
Insert the following payload:

html

<video-player source="javascript:alert('JWT: '+localStorage.getItem('jwt').substring(0,30))" source-type="external"></video-player>

Save the page.

Reload or revisit or send the page.

Result <img width="2468" height="1394" alt="image" src="https://github.com/user-attachments/assets/543bbf69-900d-4e2d-bd6b-0658fb5aa899" />

A JavaScript alert executes. The JWT token is exposed. This confirms arbitrary JavaScript execution in the victim’s browser.

Impact

This vulnerability allows stored XSS leading to:

Theft of JWT authentication tokens
Session hijacking
Full account takeover
Execution of arbitrary JavaScript in victim browsers

If an administrator views a malicious page, this can lead to full CMS compromise.

Attack complexity: Low Privileges required: Low (any authenticated user) User interaction: Required

AnalysisAI

Stored cross-site scripting in HAX CMS (npm packages @haxtheweb/haxcms-nodejs and @haxtheweb/video-player versions <= 25.0.0) allows any authenticated user to inject a <video-player> element whose source or source-data attribute carries a javascript: URI that executes when other users render the page. A public PoC in the vendor's GHSA advisory demonstrates JWT theft from localStorage, enabling session hijacking and full account takeover - especially severe when an administrator views the malicious page. No public exploit identified at time of analysis beyond the advisory PoC, and the issue is not listed in CISA KEV.

Technical ContextAI

HAX CMS is a headless, web-component-based content management system from The Pennsylvania State University's HAXTheWeb project, distributed as npm packages including @haxtheweb/haxcms-nodejs (the Node.js backend) and @haxtheweb/video-player (a Lit-based custom element). The root cause maps to CWE-79 (Improper Neutralization of Input During Web Page Generation), specifically the absence of URI-scheme validation on the source and source-data attributes of the <video-player> custom element. Because custom elements forward attribute values directly into DOM properties such as media src bindings, accepting the javascript: pseudo-scheme without an allowlist (e.g., http/https/data of safe MIME types) lets attacker-controlled script execute under the CMS origin, which holds the JWT used for authenticated CMS API calls.

RemediationAI

Vendor-released patch: upgrade @haxtheweb/haxcms-nodejs and @haxtheweb/video-player to 26.0.0 or later via npm install @haxtheweb/haxcms-nodejs@^26 @haxtheweb/video-player@^26 and redeploy the CMS, per advisory GHSA-2m6p-hm3w-6jm3 (https://github.com/haxtheweb/issues/security/advisories/GHSA-2m6p-hm3w-6jm3). If immediate upgrade is not possible, compensating controls include server-side sanitization of stored HTML to strip any <video-player> element whose source or source-data attribute does not start with http://, https://, or a vetted relative path (this will break legitimate non-HTTP sources), restricting the HTML source editor (<>) to highly trusted roles only to reduce the pool of potential injectors, and moving the JWT out of localStorage into an HttpOnly cookie so a successful XSS cannot trivially exfiltrate the session token (note: this requires CSRF protections and CMS code changes). A strict Content-Security-Policy that forbids inline script and disallows javascript: URIs (script-src 'self'; ... without unsafe-inline) will also neutralize the PoC, with the trade-off of breaking any HAX components that rely on inline handlers.