Published: November 1, 2026 | Last Modified: November 1, 2026
Legacy (v1 to v3) Actions artifact uploads stored the request's `Content-Encoding` header unchecked in the column that is served as the artifact's `Content-Type` on download, and a value starting with `video/` or `audio/` also removed the sandboxing Content-Security-Policy. A user who can run an Actions job could upload an artifact that a browser renders as HTML on the Gitea origin when the direct artifact download URL is opened, and the URL is reachable anonymously on public repositories. A victim who opens the link runs the attacker's script with their own session, which for an administrator means control of the instance. Legacy uploads now store only the `gzip` marker, and the special serve headers are chosen only for valid media types.
Exploitation Probability (EPSS): Low — 0.23% (14th percentile)
Low exploitation probability based on current threat landscape data. Standard patching timeline is appropriate.
This analysis is generated by Ghostwire from NVD, CISA KEV, EPSS, and open-source intelligence data. Verify findings through primary sources before acting.