Improper access control in Gitea - CVE-2026-66877
Published: August 31, 2026
Vulnerability identifier: #VU146350
CSH Severity: Medium
CVSS v4: 8.4 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-66877
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary code on self-hosted runners.
The vulnerability exists due to improper access control in the fork pull request workflow approval handling when processing job-level concurrency cancellation. A remote user can open a pull request and cause a pending run to be re-evaluated through a shared job-level concurrency group to execute arbitrary code on self-hosted runners.
User interaction is required because a maintainer must handle the pull request workflow process.
Affected software
Gitea
How to mitigate CVE-2026-66877
Install security update from vendor's website.
Gitea - update to 1.27.3