Description
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
References3
- github.com/steveiliop56/tinyauth/security/advisories/GHSA-9q5m-… ExploitMitigationVendor Advisory
- github.com/steveiliop56/tinyauth/commit/f26c2171610d5c2dfbba2ed… Patch
- github.com/steveiliop56/tinyauth/releases/tag/v5.0.5 ProductRelease Notes
Metrics
- CVSS 3.1
-
7.7
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 29 · as of 12 November 2026
- CWE
- CWE-362
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