What is CVE-2026-82462?

CVE-2026-82462 is a medium-severity vulnerability in Pac4j, classified under Insufficient Verification of Data Authenticity. CVSS score: 6.5/10. Published 2026-08-29.

How severe is CVE-2026-82462?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Pac4j

CVE-2026-82462

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.

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

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (8.5th percentile), scored 2026-10-14.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 8.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001

Affected products

Pac4j

Weakness classification (CWE)

CWE-345 — Insufficient Verification of Data Authenticity

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-authentication-bypass-via-… (third-party-advisory)

Frequently asked questions

What is CVE-2026-82462?: CVE-2026-82462 is a medium-severity vulnerability in Pac4j, classified under Insufficient Verification of Data Authenticity. CVSS score: 6.5/10. Published 2026-08-29.
How severe is CVE-2026-82462?: Medium severity. CVSS v3 base score is 6.5 out of 10.