The vulnerability allows a Gitea Actions job to authenticate as the gitea-actions system user, enabling the job to register an email address and a GPG key on that user without email confirmation. Because the key is not linked to a real owner, commit verification treats it as the instance signing key. Consequently, any user who can run a workflow job can make commits signed with their own key appear to be legitimately instance‑signed in all repositories where the key is present, including pull requests to repositories to which the user has no write permission. The impact is limited to the displayed signature status; enforcement mechanisms that require signed commits check only that a signature is valid, so no actual access or control over repository content is obtained.

The affected vendor is Gitea, product Gitea. Any Gitea instance running a version prior to the 28.3.0 release is susceptible to the token‑spoofing flaw. The published fix is included in the 28.3.0 release and later versions.

The vulnerability does not provide a path to denial of service or arbitrary code execution, and the exploit probability is unknown because EPSS data is missing. It is listed as not present in the CISA KEV catalog. The primary attack vector requires an attacker to be able to execute a Gitea Actions workflow job, which typically means possessing push or workflow‑execution permissions on a repository. Because the flaw only affects signature verification, the risk level is moderate, but the lack of confirmed exploitation data means it is unlikely to be widely targeted. The CVSS score is not supplied, so severity assessment must rely on the described limitations.