# CVE-2026-104030: sssd out-of-bounds read in passkey authentication

Source: https://junglewise.ai/threats/cve-2026-104030-a-flaw-was-found-in-sssd-this-vulnerability-allows-a-local-user  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-05. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-104030 · Severity: medium · CVSS 5.5 · Published 2026-10-05

sssd is a system service that authenticates users on Linux systems. A local attacker can crash the authentication service by submitting a malformed passkey token, temporarily preventing legitimate users from logging in and disrupting system availability.

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

## Quick answers

**Is CVE-2026-104030 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-104030 being exploited in the wild.

**How severe is CVE-2026-104030?** Medium severity, with a CVSS score of 5.5, published 5 October 2026.

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

**Is there a fix for CVE-2026-104030?** 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-2026-104030 attacked?** It is attacked with local access, in a hosted service.

**Am I affected by CVE-2026-104030?** 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

An out-of-bounds read vulnerability (CWE-125) exists in sssd's PAM responder when parsing passkey authentication tokens that lack null terminators. A local unprivileged attacker can trigger a buffer over-read that causes the sssd process to crash, disrupting authentication services. The vulnerability requires local system access and does not permit privilege escalation or code execution.

## Affected products

- sssd sssd

## Timeline

- 2026-10-05: 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-2026-104030](https://access.redhat.com/security/cve/CVE-2026-104030)

## 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 null pointer dereference in certificate SID mapping](https://junglewise.ai/threats/cve-2026-104038-a-flaw-was-found-in-sssd-a-remote-attacker-can-cause-a-denial-of)