CVE-2026-104034 Sssd: sssd: denial of service via use-after-free in kcm ticket renewal
An authenticated local user can crash the SSSD KCM responder via a use-after-free during ticket renewal, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-104034?
CVE-2026-104034 is a medium-severity use after free vulnerability in Red Hat Enterprise Linux 10, published on 6 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A flaw was found in SSSD. A use-after-free vulnerability exists in the Kerberos Credential Manager (KCM) responder during Kerberos ticket-granting ticket (TGT) renewal, where a deferred callback accesses memory that has already been released. An authenticated local user with a renewable Kerberos ticket can trigger this issue on systems configured with KCM renewal, causing the KCM responder service to crash and resulting in a Denial of Service (DoS).
Weakness: CWE-825
Which versions are affected by CVE-2026-104034?
How do I fix CVE-2026-104034?
No fix has been published for CVE-2026-104034 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-104034 being exploited?
There is no known exploitation of CVE-2026-104034 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-104034, GHSA-fcpm-98rx-c93x, UBUNTU-CVE-2026-104034.