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

No history.

Information

Published : 2026-04-02 15:16

Updated : 2026-06-17 10:37

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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