CVE-2026-33544: Tinyauth

High severity, CVSS 7.7. EPSS: 0.3% chance of exploitation in the next 30 days.

Tinyauth is an authentication and authorization server. Prior to version 5.0.5, all three OAuth service implementations (GenericOAuthService, GithubOAuthService, GoogleOAuthService) store PKCE verifiers and access tokens as mutable struct fields on singleton instances shared across all concurrent requests. When two users initiate OAuth login for the same provider concurrently, a race condition between VerifyCode() and Userinfo() causes one user to receive a session with the other user's identity. This issue has been patched in version 5.0.5.

Affected products

• Tinyauth Tinyauth: before 5.0.5 (fixed in 5.0.5)

Published 2026-04-02. Last modified 2026-06-17.