What’s Vulnerable › Vulnerabilities

CVE-2026-82461: pac4j-oidc before 6.5.6 Privilege Escalation via Unverified Keycloak Access Token

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-29 · updated 2026-09-10
• Weakness: CWE-347

Description

pac4j-oidc before 6.5.6 fails to verify access token signatures, issuers, audiences, or expiry when extracting Keycloak realm and client roles. Attackers can forge access tokens with administrative roles paired with valid ID tokens to bypass authorization checks in applications relying on pac4j role validation.

Affected products

• pac4j: before 6.5.6 — fixed in 6.5.6

How to fix

Upgrade to a fixed version: pac4j 6.5.6. Check the vendor advisory for mitigations.

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/authorization/generator/KeycloakRolesAuthorizationGenerator.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-privilege-escalation-via-unverified-keycloak-access-token

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