High severity · published Oct 14, 2026
CVE-2026-66877
Gitea fork workflow approval bypass through concurrency cancellation
8.1
CVSS
0.4%
EPSS
No
On KEV
Description
Gitea enforces first-time fork contributor approval by blocking jobs, but some job transition and dispatch paths do not re-check the run's approval requirement. A separate run sharing a job-level concurrency group can cancel a pending job and cause its blocked sibling jobs to be re-emitted and dispatched without approval. This allows unreviewed workflow code to execute on self-hosted runners; fork secrets remain withheld and the run token remains read-only.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GI
Gitea · Gitea
through 1.27.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-66877
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-66877
vendor-advisory
https://github.com/go-gitea/gitea/security/advisories/GHSA-v2w8-m4gr-qj65
release-notes
https://blog.gitea.com/release-of-1.27.3/
patch
https://github.com/go-gitea/gitea/pull/39005
patch
https://github.com/go-gitea/gitea/pull/39018
release-notes
https://github.com/go-gitea/gitea/releases/tag/v1.27.3
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