CVE-2026-33500 Details
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](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.
A stored cross-site scripting vulnerability has been identified in WWBN AVideo versions through 26.0. The issue arises from a bypass in the custom 'ParsedownSafeWithLinks' class, which was introduced as a fix for a previous vulnerability. This class is supposed to sanitize raw HTML links and images in comments, but it disables Parsedown's 'safeMode', which normally filters out unsafe 'javascript:' URLs. As a result, an attacker can exploit this by injecting markdown links that include 'javascript:' URIs, bypassing the intended sanitization and injecting malicious scripts that are executed when the comment is viewed.
Users can update to the patched version of WWBN AVideo, which is available in the GitHub repository.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Mar 24, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/WWBN/AVideo/commit/3ae02fa240939dbefc5949d64f05790fd25d728d | [email protected] | Patch |
| https://github.com/WWBN/AVideo/security/advisories/GHSA-72h5-39r7-r26j | [email protected] | ExploitMitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| wwbn avideo | <= 26.0 |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Mar 24, 2026 | Initial Analysis | [email protected] |
| Mar 23, 2026 | New CVE Received | [email protected] |