CVE-2026-33544
HIGHTinyauth has OAuth account confusion via shared mutable state on singleton service instances
Title source: cnaDescription
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.
References (3)
Core 3
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/steveiliop56/tinyauth/security/advisories/GHSA-9q5m-jfc4-wc92
X_Refsource_Misc x_refsource_misc
https://github.com/steveiliop56/tinyauth/commit/f26c2171610d5c2dfbba2edb6ccd39490e349803
X_Refsource_Misc x_refsource_misc
https://github.com/steveiliop56/tinyauth/releases/tag/v5.0.5
Scores
CVSS v3
7.7
EPSS
0.0034
EPSS Percentile
25.4%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
total
Details
CWE
CWE-362
Status
published
Products (3)
steveiliop56/tinyauth
0 - 1.0.1-0.20260401140714-fc1d4f2082a5Go
steveiliop56/tinyauth
< 5.0.5
tinyauth/tinyauth
< 5.0.5
Published
Apr 02, 2026
Tracked Since
Apr 02, 2026