{"id":"CVE-2026-66877","state":"PUBLISHED","title":"Gitea fork workflow approval bypass through concurrency cancellation","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.","publishedAt":"2026-10-14T14:36:11.356Z","updatedAt":"2026-10-15T03:56:53.515Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","source":"CISA-ADP"},"assigner":"Gitea","products":["Gitea Gitea"],"affected":[{"vendor":"Gitea","product":"Gitea","packageName":"code.gitea.io/gitea","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"1.27.2","versionType":"semver"}]}],"references":["https://github.com/go-gitea/gitea/security/advisories/GHSA-v2w8-m4gr-qj65","https://blog.gitea.com/release-of-1.27.3/","https://github.com/go-gitea/gitea/pull/39005","https://github.com/go-gitea/gitea/pull/39018","https://github.com/go-gitea/gitea/releases/tag/v1.27.3"],"weaknesses":["CWE-284"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/66xxx/CVE-2026-66877.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-66877","state":"PUBLISHED","datePublished":"2026-10-14T14:36:11.356Z","dateUpdated":"2026-10-15T03:56:53.515Z","assignerShortName":"Gitea","assignerOrgId":"88ee5874-cf24-4952-aea0-31affedb7ff2","dateReserved":"2026-08-13T16:50:58.698Z"},"containers":{"cna":{"title":"Gitea fork workflow approval bypass through concurrency cancellation","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Gitea","product":"Gitea","packageName":"code.gitea.io/gitea","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"1.27.2","versionType":"semver"}]}],"references":[{"url":"https://github.com/go-gitea/gitea/security/advisories/GHSA-v2w8-m4gr-qj65","name":"GitHub Security Advisory GHSA-v2w8-m4gr-qj65","tags":["vendor-advisory"]},{"url":"https://blog.gitea.com/release-of-1.27.3/","name":"Gitea 1.27.3 release announcement","tags":["release-notes"]},{"url":"https://github.com/go-gitea/gitea/pull/39005","name":"Fix: go-gitea/gitea pull request #39005","tags":["patch"]},{"url":"https://github.com/go-gitea/gitea/pull/39018","name":"Fix: go-gitea/gitea pull request #39018","tags":["patch"]},{"url":"https://github.com/go-gitea/gitea/releases/tag/v1.27.3","name":"go-gitea/gitea v1.27.3 release","tags":["release-notes"]}],"providerMetadata":{"shortName":"Gitea","orgId":"88ee5874-cf24-4952-aea0-31affedb7ff2","dateUpdated":"2026-10-14T14:36:11.356Z"},"credits":[{"lang":"en","value":"https://github.com/klydz","type":"reporter"},{"lang":"en","value":"https://github.com/bircni","type":"remediation developer"}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":8.1,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"LOW","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-10-14T00:00:00+00:00","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3","id":"CVE-2026-66877"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-284","type":"CWE","lang":"en","description":"CWE-284 Improper Access Control"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T03:56:53.515Z"}}]}}}