CVE-2026-33500
March 23, 2026
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](javascript:alert(1))" 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.
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Contact UsCVSS v4
Base Score:
5.1
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
PASSIVE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
LOW
Subsequent System Integrity
LOW
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.4
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
EPSS
Base Score:
0.03
