Gitea EUVD-2026-58167

Exploitation requires the attacker to have previously held admin-level collaboration permission on a private Gitea repository, specifically sufficient permission to create repository-level webhooks (a capability restricted to admin collaborators, not base collaborators). The attacker must configure a webhook pointing to an endpoint they control before their access is revoked. After revocation, no authentication, network access to the Gitea instance, or further attacker interaction is required - the exfiltration is fully passive. Exploitation is limited to Gitea instances running versions prior to 1.27.0. The attack is constrained to repository events that occur after the webhook is created; historical content is not retroactively exposed. The exfiltration is invisible to repository owners unless they manually inspect the webhook list, as Gitea generates no alert on delivery to a webhook whose creator is no longer a collaborator.

The provided CVSS 3.1 vector AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N yields a score of 6.8 (Medium), which accurately reflects the threat model: the PR:H prerequisite (prior admin collaboration on the targeted repository) substantially limits the attack surface, while S:C and C:H capture that once established, full event payloads - issue bodies, commit data, repository metadata - cross the revoked authorization boundary to an attacker-controlled endpoint. No CISA KEV listing exists and no public proof-of-concept has been identified, suggesting EPSS is low; however, the attack requires no technical sophistication once the precondition is met and would be naturally discovered by any former admin collaborator who notices their webhook remains active. SSVC assessment: exploitation status is none publicly confirmed; automatable is yes post-setup (no further attacker interaction needed); technical impact is partial (confidentiality only). The real-world risk is elevated specifically for organizations that routinely onboard and offboard external collaborators on private repositories, as the exfiltration is persistent and produces no owner-visible alert. CVSS and EPSS signals are consistent - this is a genuine medium priority, not a deprioritized high-CVSS issue.

An attacker who holds admin collaborator access on a target private Gitea repository creates a webhook pointing to an endpoint they control, then waits for - or engineers - their access to be revoked by the repository owner. Despite the revocation, Gitea's DeleteCollaboration() leaves the webhook intact and active; every subsequent repository event (new issues, comments, commits, PR activity) delivers the full JSON payload - including issue titles, bodies, commit messages, and the repository.private:true flag - to the attacker's endpoint with no further action required. The repository owner sees no indication of the ongoing disclosure absent a manual webhook audit.