CVE-2026-82462

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.

References

• https://github.com/pac4j/pac4j
• https://github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-oidc/src/main/java/org/pac4j/oidc/credentials/extractor/OidcCredentialsExtractor.java
• https://github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e
• https://www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html
• https://www.vulncheck.com/advisories/pac4j-oidc-before-6.5.6-authentication-bypass-via-access-token-substitution