CVE-2026-26247: Gitea OAuth2 PKCE S256 verifier bypass
(updated )
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.
References
- blog.gitea.com/release-of-1.25.5
- github.com/advisories/GHSA-m5ch-ppfx-xv3v
- github.com/go-gitea/gitea/commit/750649c1ef092c95f95b206b9d5fa17471a0b1f5
- github.com/go-gitea/gitea/commit/bf8d11bb212ba2a76596d8a90e74e7d664571324
- github.com/go-gitea/gitea/pull/36462
- github.com/go-gitea/gitea/pull/36477
- github.com/go-gitea/gitea/releases/tag/v1.25.5
- nvd.nist.gov/vuln/detail/CVE-2026-26247
Code Behaviors & Features
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