CVE-2026-82462
pac4j-oidc before 6.5.6 Authentication Bypass via Access Token Substitution
- State
- Published
- Severity
- 6.9 Medium
- Published
- Aug 29, 2026
- Updated
- Aug 31, 2026
- Reserved
- Aug 29, 2026
Description
pac4j-oidc before 6.5.6 accepts OIDC callbacks carrying only an access token without authorization code or ID token validation. Attackers can substitute access tokens minted for other clients to create authenticated sessions without proper issuer, audience, nonce, or subject verification.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N | VulnCheck |
Weaknesses
- CWE-345 Insufficient Verification of Data Authenticity
Affected Products
| Product | Versions |
|---|---|
pac4jpac4j |
|
References
- Patch Commitpatch
- pac4j Security Advisory for pac4j-core, pac4j-oidc and pac4j-samlvendor-advisory
- https://github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-oidc/src/main/java/org/pac4j/oidc/credentials/extractor/OidcCredentialsExtractor.javatechnical-description
- https://github.com/pac4j/pac4jproduct
- VulnCheck Advisory: pac4j-oidc before 6.5.6 Authentication Bypass via Access Token Substitutionthird-party-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.