pac4j-oidc before 6.5.6 Privilege Escalation via Unverified Keycloak Access Token

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-82461
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-29 17:17:58 UTC
Updated2026-08-29 17:17:58 UTC
Descriptionpac4j-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.

Risk And Classification

Primary CVSS: v4.0 8.6 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-347 | CWE-347 Improper Verification of Cryptographic Signature

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.6HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS8.6HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
3.1[email protected]Primary8.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
3.1CNACVSS8.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Pac4j Pac4j affected 6.5.6 semver Not specified

References

ReferenceSourceLinkTags
github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e [email protected] github.com
www.vulncheck.com/advisories/pac4j-oidc-before-6.5.6-privilege-escalation-via-u... [email protected] www.vulncheck.com
www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html [email protected] www.pac4j.org
github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-oidc/src/main/java/... [email protected] github.com
github.com/pac4j/pac4j [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Joshua Rogers (AISLE Research) (en)

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