pac4j-saml before 6.5.6 does not require signature validation of SAML LogoutRequest messages in SAML2LogoutValidator.validateLogoutRequest(). (CVE-2026-82465)
Description
pac4j-saml versions before 6.5.6 do not enforce signature validation on SAML LogoutRequest messages in the SAML2LogoutValidator.validateLogoutRequest() method. This allows an unauthenticated attacker to submit an unsigned LogoutRequest with a guessed NameID (such as an email address) to terminate a victim's SAML session when the Identity Provider (IdP) sends no SessionIndex.
CVSS v3.1
Score 5.3medium
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in pac4j-saml prior to version 6.5.6 involves the lack of mandatory signature validation for SAML LogoutRequest messages within the SAML2LogoutValidator.validateLogoutRequest() function. Specifically, when the IdP omits the SessionIndex, the session termination logic relies solely on the NameID. An attacker can exploit this by submitting an unsigned LogoutRequest with a guessed NameID, enabling them to forcibly terminate a victim's SAML session without authentication.
Potential Impact
An unauthenticated attacker can cause denial of service by terminating active SAML sessions of victims. This does not disclose information or allow session hijacking but disrupts user sessions by forcing logout.
Mitigation Recommendations
A fix is available in pac4j-saml version 6.5.6 that enforces signature validation of LogoutRequest messages. Users should upgrade to version 6.5.6 or later to remediate this vulnerability. Patch status is not explicitly confirmed in the input data, but the version boundary indicates a fix in 6.5.6. No alternative mitigations are provided.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-r76c-m8xx-m685
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-82465"]
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a944bd9acd9273b49b25bbf
Added to database: 08/30/2026, 15:27:21 UTC
Last enriched: 09/09/2026, 12:38:47 UTC
Last updated: 10/14/2026, 06:48:21 UTC
Views: 95
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.