EUVD-2026-68120
GHSA-f66h-84rm-53q7
Severity by source
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
Network-exploitable with low complexity, but PR:L because a valid (weaker) authenticated session is required; no scope change since impact stays within the same application boundary.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
3DescriptionCVE.org
pac4j-core before 6.5.6 contains an authentication bypass vulnerability in CheckProfileTypeAuthorizer that reverses the profile type validation logic. Attackers can authenticate through a weaker client and access resources requiring a stronger profile type by satisfying generic profile checks.
AnalysisAI
Authentication bypass in pac4j-core before 6.5.6 allows authenticated users holding a weaker profile type to access resources that enforce a stronger profile type requirement, due to a reversed Java class inheritance check in CheckProfileTypeAuthorizer. The single-character logical inversion - swapping the operands of isAssignableFrom - causes the authorizer to grant access when a base/generic profile is presented against a check expecting a specific subtype (e.g., SAML or OIDC profile), instead of blocking it. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The application must use pac4j-core's CheckProfileTypeAuthorizer to enforce profile-type-based access control - this is the specific, non-default configuration required for exploitation. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 8.6 with vector AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N reflects a high-severity but not maximally critical issue: network-exploitable, low complexity, but requiring prior authentication (PR:L). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade pac4j-core to version 6.5.6 or later, which contains the confirmed fix per the vendor advisory at https://www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html and commit https://github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all systems using pac4j-core and identify which versions are deployed; prioritize production environments. …
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LDAP injection vulnerabilities in PAC4J authentication library allow low-privileged remote attackers to execute arbitrar
Privilege escalation in pac4j-oidc before 6.5.6 allows authenticated attackers to forge Keycloak access tokens and claim
CSRF protection bypass in PAC4J authentication library allows remote attackers to forge state-changing requests without
Session termination via unsigned SAML LogoutRequest in pac4j-saml before 6.5.6 allows unauthenticated remote attackers t
Authentication bypass in pac4j-oidc before 6.5.6 allows remote unauthenticated attackers to establish authenticated sess
Open redirect in pac4j-core before 6.5.6 allows network-accessible attackers to redirect authenticated users to attacker
The SAML identifier generated within SAML2Utils.java was found to make use of the apache commons-lang3 RandomStringUtils
Same weakness CWE-863 – Incorrect Authorization
View allSame technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today