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.
Fix
Patch, vendor advisory and mitigation references on NVD 2
- https://github.com/steveiliop56/tinyauth/commit/f26c2171610d5c2dfbba2edb6ccd39490e349803 Patch
- https://github.com/steveiliop56/tinyauth/security/advisories/GHSA-9q5m-jfc4-wc92 Exploit, Mitigation, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.7 · tinyauthNVD modified 2026-10-26 22:10
Affected (CPE criteria) 1
cpe:2.3:a:tinyauth:tinyauth:*:*:*:*:*:*:*:*
References 3
- https://github.com/steveiliop56/tinyauth/commit/f26c2171610d5c2dfbba2edb6ccd39490e349803 Patch
- https://github.com/steveiliop56/tinyauth/releases/tag/v5.0.5 Product, Release Notes
- https://github.com/steveiliop56/tinyauth/security/advisories/GHSA-9q5m-jfc4-wc92 Exploit, Mitigation, Vendor Advisory