Marker up to version 2.0.0 contains a path traversal flaw in the FastAPI /marker/upload handler. The server fails to sanitize the file.filename parameter, allowing an unauthenticated attacker to supply filenames that traverse directories. This flaw permits the attacker to upload files to arbitrary locations on the host filesystem or delete existing files, creating a serious risk of remote code execution, data loss, and denial of service.

The vulnerability affects the datalab-to Marker application, specifically all releases up to and including version 2.0.0. No other versions are currently listed as affected.

The CVSS score of 8.8 indicates a high severity. Because the exploit requires only an unauthenticated HTTP request and the payload is simple, the likelihood of exploitation is high. The EPSS score is unavailable, and the vulnerability is not listed in the CISA KEV catalog, but the combination of high CVSS and path traversal susceptibility suggests that attackers could readily target any exposed instance of Marker.