Session Hijacking Vulnerability in Gitea's OAuth2 and OpenID Connect Authentication
CVE-2026-73278

9.8CRITICAL

Key Information:

Vendor

Gitea

Status
Gitea
Vendor
CVE Published:
6 October 2026

What is CVE-2026-73278?

Gitea has identified a weakness in its OAuth2 and OpenID Connect sign-in mechanisms. Specifically, when users configure WebAuthn as their only second-factor authentication method, the system fails to mandate a WebAuthn challenge during authentication. This gap allows an attacker who gains access through vulnerable external identity flows to establish a complete session on behalf of the user without the necessary passkey verification imposed during regular password-based logins. Moreover, this vulnerability may facilitate the persistence of an external identity link, consequently extending the potential security compromise across multiple sessions. It is noteworthy that accounts utilizing Time-based One-Time Password (TOTP) are exempt from this specific issue.

Affected Version(s)

Gitea 1.16.0 <= 1.27.1

References

https://github.com/go-gitea/gitea/security/advisories/GHS...
vendor-advisory
https://blog.gitea.com/release-of-1.27.2/
release-notes
https://github.com/go-gitea/gitea/pull/38805
patch

CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

https://github.com/MindflareX
https://github.com/AdamKorcz
https://github.com/jaeyoon-kim-dev
.