# CVE-2026-127101: SSSD PAM responder NULL pointer dereference

Source: https://junglewise.ai/threats/cve-2026-127101-a-flaw-was-found-in-sssd-s-pam-responder-a-local-attacker-can  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-12. Updated: 2026-11-12  
License: CC BY 4.0 with a link back

CVE-2026-127101 · Severity: medium · CVSS 5.5 · Published 2026-11-12

SSSD is a security service daemon that handles user authentication for Linux systems. A local attacker can crash SSSD's PAM responder by sending a crafted authentication request, disrupting all user logins on the system. An attacker with local access could repeatedly trigger this crash to sustain a denial of service against legitimate authentication requests.

Technologies: [SSSD Project SSSD](https://junglewise.ai/threats/technologies/sssd). Vendors: [SSSD Project](https://junglewise.ai/threats/vendors/sssd-project).

## Quick answers

**Is CVE-2026-127101 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-127101 being exploited in the wild.

**How severe is CVE-2026-127101?** Medium severity, with a CVSS score of 5.5, published 12 November 2026.

**Which products and versions are affected?** SSSD Project SSSD.

**Is there a fix for CVE-2026-127101?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-127101 attacked?** It is attacked with local access, in a hosted service.

**Am I affected by CVE-2026-127101?** Check whether you run SSSD Project SSSD. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A NULL pointer dereference vulnerability exists in SSSD's PAM responder when a local attacker sends an authentication request before completing client protocol version negotiation. The responder fails to validate the protocol-version pointer and crashes, preventing PAM authentication. Attack requires local access to the PAM responder socket and low privileges; repeated requests sustain denial of service.

## Affected products

- SSSD Project SSSD

## Timeline

- 2026-11-12: disclosed

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-127101](https://access.redhat.com/security/cve/CVE-2026-127101)

## Related threats

- [sssd responder denial of service via file descriptor exhaustion](https://junglewise.ai/threats/cve-2026-88252-a-flaw-was-found-in-sssd-a-local-user-can-cause-a-denial-of)
- [SSSD NFS idmap plugin out-of-bounds write](https://junglewise.ai/threats/cve-2026-104036-a-flaw-was-found-in-sssd-s-nfs-idmap-plugin-when-retrieving)
- [SSSD Kerberos Credential Manager memory exhaustion denial of service](https://junglewise.ai/threats/cve-2026-104035-a-flaw-was-found-in-sssd-an-issue-in-the-kerberos-credential)
- [SSSD LDAP shadow expiration bypass](https://junglewise.ai/threats/cve-2026-104033-a-flaw-was-found-in-sssd-when-configured-to-enforce-account)
- [SSSD memory leak in autofs responder](https://junglewise.ai/threats/cve-2026-104031-a-flaw-was-found-in-sssd-in-configurations-where-the-autofs)