{"id":"GHSA-m5ch-ppfx-xv3v","revision":"cdfacb80460a49fba7ea46fa8b3eb5bc","records":[{"revision":"cdfacb80460a49fba7ea46fa8b3eb5bc","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-m5ch-ppfx-xv3v","aliases":["CVE-2026-26247","GO-2026-6342"],"title":"Gitea OAuth2 PKCE S256 verifier bypass","description":"Gitea versions before 1.25.5 do not persist the OAuth2 PKCE S256 challenge method correctly during authorization, allowing token exchange without the expected verifier check.","state":0,"publishedAt":"2026-07-03T21:31:37+00:00","modifiedAt":"2026-09-02T19:41:26.2641955+00:00","affected":[{"ecosystem":"Go","name":"code.gitea.io/gitea","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"1.25.5"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"CRITICAL"}],"references":["https://nvd.nist.gov/vuln/detail/CVE-2026-26247","https://github.com/go-gitea/gitea/pull/36462","https://github.com/go-gitea/gitea/pull/36477","https://github.com/go-gitea/gitea/commit/750649c1ef092c95f95b206b9d5fa17471a0b1f5","https://github.com/go-gitea/gitea/commit/bf8d11bb212ba2a76596d8a90e74e7d664571324","https://blog.gitea.com/release-of-1.25.5","https://github.com/go-gitea/gitea","https://github.com/go-gitea/gitea/releases/tag/v1.25.5"],"sourceUrl":"https://github.com/advisories/GHSA-m5ch-ppfx-xv3v","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-m5ch-ppfx-xv3v","identifiers":["GHSA-m5ch-ppfx-xv3v","CVE-2026-26247","GO-2026-6342"]},"retained":false,"historicalAffected":[]}],"coverage":[]}