What is CVE-2026-82461?

CVE-2026-82461 is a high-severity vulnerability in Pac4j, classified under Improper Verification of Cryptographic Signature. CVSS score: 8.1/10. Published 2026-08-29.

How severe is CVE-2026-82461?

High severity. CVSS v3 base score is 8.1 out of 10.

Vulnerability in Pac4j

CVE-2026-82461

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.

Published 2026-08-29 · last modified 2026-09-10.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (22.7th percentile), scored 2026-10-14.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 22.7% 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

Pac4j

Weakness classification (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

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-oidc/src/main/java/org/pac… (technical-description)
github.com/pac4j/pac4j (product)
www.vulncheck.com/advisories/pac4j-oidc-before-6.5.6-privilege-escalation-via-u… (third-party-advisory)

Frequently asked questions

What is CVE-2026-82461?: CVE-2026-82461 is a high-severity vulnerability in Pac4j, classified under Improper Verification of Cryptographic Signature. CVSS score: 8.1/10. Published 2026-08-29.
How severe is CVE-2026-82461?: High severity. CVSS v3 base score is 8.1 out of 10.