The Gitea API routes for issue attachments (`/api/v1/repos/{owner}/{repo}/issues/{index}/assets/{attachment_id}`) also accepted attachments that belong to comments on the issue. Because the author of an issue may edit and delete the issue's attachments, a user who opened an issue could rename or delete attachments that other users had posted in comments on that issue. The contents of the attachments could not be changed.
https://github.com/go-gitea/gitea/security/advisories/GHSA-96qg-qxxj-r8xq
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