VYPR
Moderate severityNVD Advisory· Published Mar 23, 2026· Updated Mar 24, 2026

AVideo Vulnerable to Stored XSS via Markdown `javascript:` URI Bypasses ParsedownSafeWithLinks Sanitization

CVE-2026-33500

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.

PackageAffected versionsPatched versions
wwbn/avideoPackagist
<= 26.0

Affected products

1

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

4

News mentions

0

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