Gogs is a self‑hosted Git service. Prior to version 0.14.3, a repository admin collaborator may gain owner‑level access by exploiting an off‑by‑one error in the ChangeCollaborationAccessMode function. This flaw allows the attacker to bypass the validation that should prevent a collaborator from assigning their own permissions to the maximum level, thereby escalating privileges within the affected repository. The weakness is a classic example of an off‑by‑one error (CWE‑193) that enables unauthorized privilege escalation.

The vulnerability affects the Gogs platform, specifically all installations running a version older than 0.14.3. Any hosting of a local Gogs instance that permits collaborators to manage permissions is at risk. The fix is incorporated in release 0.14.3, so anyone operating an earlier release must update.

The CVSS score of 5.5 indicates moderate severity, and the EPSS score is not available, so the likelihood of exploitation cannot be quantified. The vulnerability is not listed in the CISA KEV catalog. The attack can be carried out by any collaborator with administrative privileges on a repository: the attacker performs the off‑by‑one mutation when changing the collaborator’s access mode, gaining owner rights over the repository. Because no network‑side component is required and the flaw is local to the application, the vector is likely local or web‑based through the Gogs UI, though this is inferred rather than explicitly stated in the description.