CVE-2026-26247: Gitea Open Source Git Server

Critical severity, CVSS 9.1. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Gitea Gitea Open Source Git Server: before 1.25.5 (fixed in 1.25.5)

Published 2026-07-03. Last modified 2026-07-07.