WWBN AVideo up to 20.x Markdown cross site scripting

Summaryinfo

A vulnerability was found in WWBN AVideo up to 20.x. It has been classified as problematic. This affects an unknown function of the component Markdown Handler. The manipulation leads to cross site scripting. This vulnerability is uniquely identified as CVE-2026-27568. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in WWBN AVideo up to 20.x. It has been rated as problematic. This issue affects an unknown code block of the component Markdown Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

WWBN AVideo is an open source video platform. Prior to version 21.0, AVideo allows Markdown in video comments and uses Parsedown (v1.7.4) without Safe Mode enabled. Markdown links are not sufficiently sanitized, allowing `javascript:` URIs to be rendered as clickable links. An authenticated low-privilege attacker can post a malicious comment that injects persistent JavaScript. When another user clicks the link, the attacker can perform actions such as session hijacking, privilege escalation (including admin takeover), and data exfiltration. Version 21.0 contains a fix. As a workaround, validate and block unsafe URI schemes (e.g., `javascript:`) before rendering Markdown, and enable Parsedown Safe Mode.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-27568 since 02/20/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 21.0 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch ade348ed6d28b3797162c3d9e98054fb09ec51d7 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• WWBN

Name

• AVideo

Version

• 20.x

License

• open-source

Website

• Product: https://github.com/WWBN/AVideo/

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