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.

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Pac4j Subscribe
Pac4j Subscribe

No data.

No data.

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/pac4j/pac4j cve-icon
https://github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-oidc/src/main/java/org/pac4j/oidc/credentials/extractor/OidcCredentialsExtractor.java cve-icon
https://github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e cve-icon
https://www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html cve-icon
https://www.vulncheck.com/advisories/pac4j-oidc-before-6.5.6-authentication-bypass-via-access-token-substitution cve-icon
History

Sat, 29 Aug 2026 16:45:00 +0000

Type Values Removed Values Added
Description 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.
Title pac4j-oidc before 6.5.6 Authentication Bypass via Access Token Substitution
First Time appeared Pac4j
Pac4j pac4j
Weaknesses CWE-345
CPEs cpe:2.3:a:pac4j:pac4j:*:*:*:*:*:*:*:*
Vendors & Products Pac4j
Pac4j pac4j
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-29T16:35:26.177Z

Reserved: 2026-08-29T14:11:00.606Z

Link: CVE-2026-82462

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses