CVE-2026-33544

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.

CVSS v3 7.7 HIGH

7.7^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.3 / Impact : 5.8

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required LOW

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope CHANGED

References

Link	Resource
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

Configurations

Configuration 1 (hide)

cpe:2.3:a:tinyauth:tinyauth:*:*:*:*:*:*:*:*

History

26 Oct 2026, 22:10

Type	Values Removed	Values Added
Summary		(es) Tinyauth es un servidor de autenticación y autorización. Antes de la versión 5.0.5, las tres implementaciones del servicio OAuth (GenericOAuthService, GithubOAuthService, GoogleOAuthService) almacenan verificadores PKCE y tokens de acceso como campos de estructura mutables en instancias singleton compartidas entre todas las solicitudes concurrentes. Cuando dos usuarios inician sesión OAuth para el mismo proveedor de forma concurrente, una condición de carrera entre VerifyCode() y Userinfo() hace que un usuario reciba una sesión con la identidad del otro usuario. Este problema ha sido parcheado en la versión 5.0.5.

Information

Published : 2026-04-02 15:16

Updated : 2026-10-26 22:10

NVD link : CVE-2026-33544

Mitre link : CVE-2026-33544

CVE.ORG link : CVE-2026-33544

JSON object : View

Products Affected

tinyauth

tinyauth

CWE

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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