VULNERABILITY INTELLIGENCE
CVE-2026-33544
CVSS score7.7 HIGH
EPSS probability0.35%
CISA KEVNot currently listed
Published2026-04-02
Last modified2026-10-26
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
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.
Weakness classification
- security-advisories@github.com: CWE-362
Primary references
- security-advisories@github.com — Patch
- security-advisories@github.com — Product, Release Notes
- security-advisories@github.com — Exploit, Mitigation, Vendor Advisory