CRITICALCVSS 9.1EPSS 0.5%

CVE-2026-26247

Gitea OAuth2 PKCE S256 verifier bypass

Published: 2026-07-03
Modified: 2026-09-01
EPSS percentile: 41%
Aliases: GHSA-m5ch-ppfx-xv3v
Sources: github-advisory

Summary

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 packages

Ecosystem	Package	Affected versions	Fixed versions
Go	code.gitea.io/gitea	—	1.25.5

Remediation: Upgrade to 1.25.5 or later.

References

https://github.com/advisories/GHSA-m5ch-ppfx-xv3v

Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.

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EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.