Vulnerability · Published Aug 29, 2026 · Assigned by VulnCheck
CVE-2026-82461pac4j-oidc before 6.5.6 Privilege Escalation via Unverified Keycloak Access Token
High 8.1
In plain English
A high-severity security flaw in pac4j from pac4j. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities).
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.3%top 75.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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 (as reported)
Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
References
- Patch Commit patch
- pac4j Security Advisory for pac4j-core, pac4j-oidc and pac4j-saml vendor-advisory
- https://github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-oidc/src/main/java/org/pac4j/oidc/authorization/generator/KeycloakRolesAuthorizationGenerator.java technical-description
- https://github.com/pac4j/pac4j product
- VulnCheck Advisory: pac4j-oidc before 6.5.6 Privilege Escalation via Unverified Keycloak Access Token third-party-advisory