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High 7.7Published Apr 2, 2026

CVE-2026-33544Tinyauth has OAuth account confusion via shared mutable state on singleton service instances

Updated under an hour ago ()

Does this affect you?

It affects steveiliop56 tinyauth and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
7.7 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
Weakness (CWE)
CWE-362
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
Apr 3, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
steveiliop56 tinyauth
steveiliop56:tinyauth (from the name)
before 5.0.5
CNA record
tinyauth tinyauth
tinyauth:tinyauth
before 5.0.5
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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