CVE-2026-33544
Tinyauth has OAuth account confusion via shared mutable state on singleton service instances
- State
- Published
- Severity
- 7.7 High
- Published
- Apr 2, 2026
- Updated
- Apr 3, 2026
- Reserved
- Mar 20, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.7 High | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N | GitHub_M |
Weaknesses
- CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Affected Products
| Product | Versions |
|---|---|
tinyauthsteveiliop56 |
|
References
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