Vulnerability · Published Jul 3, 2026 · Assigned by Gitea
CVE-2026-26247Gitea OAuth2 PKCE S256 challenges are not enforced during token exchange
Critical 9.1
In plain English
A critical-severity improper access control in Gitea Open Source Git Server from Gitea. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.5%top 57.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | code.gitea.io/gitea | 1.25.5 | GHSA-m5ch-ppfx-xv3v |
| Go | code.gitea.io/gitea | 1.25.5 | GO-2026-6342 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Gitea | Gitea Open Source Git Server | 0 – before 1.25.5 |
Weakness: CWE-284 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References
- GitHub Pull Request #36462 patch
- GitHub Pull Request #36477 patch
- Gitea v1.25.5 Release release-notes
- Gitea v1.25.5 Release Blog Post release-notes