# CVE-2026-90996: sssd denial of service in NSS responder via zero-length requests

Source: https://junglewise.ai/threats/cve-2026-90996-sssd-denial-of-service-in-nss-responder-via-zero-length-requests  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-14. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-90996 · Severity: medium · CVSS 4 · Published 2026-09-14

sssd is a system service that provides user authentication and account management on Linux systems. A local unprivileged user can send a specially crafted request to crash or destabilize the NSS responder component, causing authentication services to become unavailable and impacting system availability.

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

## Quick answers

**Is CVE-2026-90996 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-90996 being exploited in the wild.

**How severe is CVE-2026-90996?** Medium severity, with a CVSS score of 4, published 14 September 2026.

**Which products and versions are affected?** SSSD Project SSSD <UNKNOWN>.

**Is there a fix for CVE-2026-90996?** 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-2026-90996 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-90996?** Check whether you run SSSD Project SSSD at an affected version. 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

The vulnerability is an integer underflow (CWE-191) in sssd's Network Security Services (NSS) responder that processes incoming requests. A local unprivileged attacker can trigger a denial-of-service condition by sending a crafted request with a zero-length body to the NSS responder's local UNIX socket, causing the responder to become unstable or terminate. The attack requires local access and does not require elevated privileges or user interaction. The vulnerability affects only availability; there is no path to remote code execution or privilege escalation. No mitigation is currently available.

## Affected products

- SSSD Project sssd <UNKNOWN>

## Timeline

- 2026-09-14: disclosed
- 2026-09-14: advisory

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-90996](https://access.redhat.com/security/cve/CVE-2026-90996)

## Related threats

- [SSSD PAM responder NULL pointer dereference](https://junglewise.ai/threats/cve-2026-127101-a-flaw-was-found-in-sssd-s-pam-responder-a-local-attacker-can)
- [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)