Gitea Actions restricts workflow runs from fork pull requests until a maintainer approves the run. However, when a run is cancelled and then rerun, the system fails to re‑enforce the approval check. A contributor with write access to the Actions configuration can cancel a pending run and immediately trigger a rerun, which is queued as if it had been approved. The workflow jobs are then executed on the repository's runners with code pulled from the fork, allowing the attacker to run arbitrary code on the CI infrastructure. The flaw involves improper authorization controls (CWE‑285).

All Gitea installations with Actions enabled and running any version prior to 28.0.0 are affected. The 28.0.0 release restores proper approval checks on rer. The impact is confined to the vendor Gitea and requires an update of the affected version to mitigate.

The vulnerability can be exploited by any user with write access to the Actions configuration, a privilege commonly granted within repositories. Once the attacker cancels and reruns a waiting job, the unverified code executes on the shared runners. The CVSS score of 8.8 indicates high severity, while an EPSS score of less than 1% suggests a low probability of widespread exploitation. Despite this, the ability to execute arbitrary code on operational CI runners makes the risk severe, and the vulnerability is not yet catalogued in CISA's KEV.