AVideo Vulnerable to Stored XSS via Markdown `javascript:` URI Bypasses ParsedownSafeWithLinks Sanitization
Description
WWBN AVideo is an open source video platform. In versions up to and including 26.0, the fix for CVE-2026-27568 (GHSA-rcqw-6466-3mv7) introduced a custom ParsedownSafeWithLinks class that sanitizes raw HTML <a> and <img> tags in comments, but explicitly disables Parsedown's safeMode. This creates a bypass: markdown link syntax `text) is processed by Parsedown's inlineLink() method, which does not go through the custom sanitizeATag() sanitization (that only handles raw HTML tags). With safeMode disabled, Parsedown's built-in javascript: URI filtering (sanitiseElement()/filterUnsafeUrlInAttribute()`) is also inactive. An attacker can inject stored XSS via comment markdown links. Commit 3ae02fa240939dbefc5949d64f05790fd25d728d contains a patch.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
wwbn/avideoPackagist | <= 26.0 | — |
Affected products
1Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
4- github.com/advisories/GHSA-72h5-39r7-r26jghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-33500ghsaADVISORY
- github.com/WWBN/AVideo/commit/3ae02fa240939dbefc5949d64f05790fd25d728dghsax_refsource_MISCWEB
- github.com/WWBN/AVideo/security/advisories/GHSA-72h5-39r7-r26jghsax_refsource_CONFIRMWEB
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