# CVE-2026-104038: sssd null pointer dereference in certificate SID mapping

Source: https://junglewise.ai/threats/cve-2026-104038-a-flaw-was-found-in-sssd-a-remote-attacker-can-cause-a-denial-of  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-06. Updated: 2026-10-06  
License: CC BY 4.0 with a link back

CVE-2026-104038 · Severity: medium · CVSS 5.9 · Published 2026-10-06

sssd is a system service that manages user authentication and identity in Linux environments, especially for enterprise deployments. A flaw allows a remote attacker to crash the authentication service by submitting a certificate missing a required Security Identifier extension, causing denial of service during login or user lookup operations on systems configured with SID-based certificate mapping.

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

## Quick answers

**Is CVE-2026-104038 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-104038 being exploited in the wild.

**How severe is CVE-2026-104038?** Medium severity, with a CVSS score of 5.9, published 6 October 2026.

**Which products and versions are affected?** sssd sssd.

**Is there a fix for CVE-2026-104038?** 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-2026-104038 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-104038?** Check whether you run 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 (CWE-476) occurs in sssd when processing certificates configured with LDAPU1 SID-based mapping rules. The service fails to verify the presence of the Microsoft SID extension before dereferencing it, causing the process to crash during certificate-driven authentication or lookup operations. Attack requires network access and an uncommon, non-default certificate mapping configuration.

## Affected products

- sssd sssd

## Timeline

- 2026-10-06: 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-2026-104038](https://access.redhat.com/security/cve/CVE-2026-104038)

## Related threats

- [SSSD NSS responder memory exhaustion via unbounded negative cache](https://junglewise.ai/threats/cve-2026-104041-a-flaw-was-found-in-sssd-an-unprivileged-local-user-can)
- [sssd out-of-bounds read in passkey authentication](https://junglewise.ai/threats/cve-2026-104030-a-flaw-was-found-in-sssd-this-vulnerability-allows-a-local-user)