CVAT versions 2.68.0 through 2.69.x contain an XSS vulnerability (CWE-80) in the audio-task annotation guide renderer component. The renderer passes user-editable Markdown content to the MDEditor without the rehype-sanitize plugin, enabling stored XSS attacks. An attacker with permission to create or edit annotation guides can embed malicious JavaScript that executes in the context of other users viewing the guide, potentially allowing unauthorized actions within CVAT under the victim's privileges. The vulnerability has a CVSS 4.0 score of 8.5 (high severity) and is fixed in version 2.70.0.

Successful exploitation allows an attacker with annotation guide edit permissions to execute arbitrary JavaScript in the context of other CVAT users who view the affected guide. This can lead to unauthorized CVAT requests being made with the victim's privileges, potentially compromising user data or system integrity within CVAT. There is no indication of privilege escalation beyond the victim's existing rights. No known exploits in the wild have been reported.

Upgrade CVAT to version 2.70.0 or later, where this vulnerability is fixed by adding proper sanitization of the Markdown content in the audio-task annotation guide renderer. Until upgrading, restrict permissions to create or edit annotation guides to trusted users only to reduce risk. Patch status is confirmed fixed in 2.70.0.