{"id":"GHSA-m5ch-ppfx-xv3v","summary":"Gitea OAuth2 PKCE S256 verifier bypass","details":"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.","aliases":["CVE-2026-26247","GO-2026-6342"],"modified":"2026-09-02T19:40:41.198617127Z","published":"2026-07-03T21:31:37Z","database_specific":{"github_reviewed_at":"2026-09-01T17:23:03Z","nvd_published_at":"2026-07-03T21:16:58Z","cwe_ids":["CWE-284"],"severity":"CRITICAL","github_reviewed":true},"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26247"},{"type":"WEB","url":"https://github.com/go-gitea/gitea/pull/36462"},{"type":"WEB","url":"https://github.com/go-gitea/gitea/pull/36477"},{"type":"WEB","url":"https://github.com/go-gitea/gitea/commit/750649c1ef092c95f95b206b9d5fa17471a0b1f5"},{"type":"WEB","url":"https://github.com/go-gitea/gitea/commit/bf8d11bb212ba2a76596d8a90e74e7d664571324"},{"type":"WEB","url":"https://blog.gitea.com/release-of-1.25.5"},{"type":"PACKAGE","url":"https://github.com/go-gitea/gitea"},{"type":"WEB","url":"https://github.com/go-gitea/gitea/releases/tag/v1.25.5"}],"affected":[{"package":{"name":"code.gitea.io/gitea","ecosystem":"Go","purl":"pkg:golang/code.gitea.io/gitea"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.25.5"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-m5ch-ppfx-xv3v/GHSA-m5ch-ppfx-xv3v.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}