Auth bypass in Steveiliop56 Tinyauth
CVE-2026-32245
Tinyauth is an authentication and authorization server. Prior to 5.0.3, the OIDC token endpoint does not verify that the client exchanging an authorization code is the same client the code was issued to. A malicious OIDC client operator can exchange another client's authorization code using their own client credentials, obtaining tokens for users who never authorized their application. This violates RFC 6749 Section 4.1.3. This vulnerability is fixed in 5.0.3.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (24.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001
Affected products
- Steveiliop56 Tinyauth — versions < 5.0.3
- Tinyauth
Weakness classification (CWE)
References
- github.com/steveiliop56/tinyauth/security/advisories/GHSA-xg2q-62g2-cvcm (Exploit, Third Party Advisory)
- github.com/steveiliop56/tinyauth/commit/b2a1bfb1f532e87f205fa3afa3fc9f148c53ab89 (Patch)
- github.com/steveiliop56/tinyauth/releases/tag/v5.0.3 (Release Notes)
Frequently asked questions
- What is CVE-2026-32245?
- CVE-2026-32245 is a medium-severity vulnerability in Steveiliop56 Tinyauth, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-03-12.
- How severe is CVE-2026-32245?
- Medium severity. CVSS v3 base score is 6.5 out of 10.