The Gitea API endpoint `GET /api/v1/repos/{owner}/{repo}/media/{filepath}` wrote files of up to 1 KiB that are stored directly in Git, not in LFS, to the response without the content type and disposition headers Gitea uses for user content. An HTML file committed to a repository was therefore rendered by the browser on the Gitea origin. A user who can push to a repository could run JavaScript in the session of a victim who opens the media URL and act with the victim's permissions.
https://github.com/go-gitea/gitea/security/advisories/GHSA-94rx-fqm6-q23v
https://github.com/go-gitea/gitea/releases/tag/v28.1.0
https://github.com/go-gitea/gitea/pull/39507
https://github.com/go-gitea/gitea/pull/39501