Vulnerability in Pac4j
CVE-2026-82465
pac4j-saml before 6.5.6 does not require signature validation of SAML LogoutRequest messages in SAML2LogoutValidator.validateLogoutRequest(). When an IdP sends no SessionIndex, a session can be destroyed based solely on the NameID, allowing an unauthenticated attacker to submit an unsigned LogoutRequest with a guessed identifier (e.g., an email address used as NameID) to terminate a victim's SAML session.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.003 (16.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 16.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e (patch)
- www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html (vendor-advisory)
- github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-saml/src/main/java/org/pac… (technical-description)
- github.com/pac4j/pac4j (product)
- www.vulncheck.com/advisories/pac4j-saml-before-6.5.6-session-destruction-via-un… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-82465?
- CVE-2026-82465 is a medium-severity vulnerability in Pac4j, classified under Insufficient Verification of Data Authenticity. CVSS score: 5.3/10. Published 2026-08-29.
- How severe is CVE-2026-82465?
- Medium severity. CVSS v3 base score is 5.3 out of 10.