CVE-2026-80928 smack: fix cred UAF in smack_file_send_sigiotask()
A use-after-free vulnerability in the Linux kernel's SMACK security module allows attackers to potentially execute code or escalate privileges via a race condition.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80928?
CVE-2026-80928 is a high-severity use after free vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
smack: fix cred UAF in smack_file_send_sigiotask()
When inspecting the credentials of another task, objective credentials (->real_cred, accessed with __task_cred()) must always be used.
Accessing ->cred on a non-current task is forbidden unless that task is being created or destroyed; a task is allowed to change its own ->cred pointer with no synchronization, and changing ->cred should only affect the current syscall.
smack_file_send_sigiotask() was accessing both sets of credentials: First tsk->cred, then __task_cred(tsk).
Fix it, always access the objective credentials here.
I have tested that this bug can lead to a KASAN-reported UAF of struct cred in smack_file_send_sigiotask(), and that this fix prevents the race.
Which versions are affected by CVE-2026-80928?
How do I fix CVE-2026-80928?
Apply the vendor's patch.
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-2026-80928 being exploited?
There is no known exploitation of CVE-2026-80928 in the wild and no public exploit code.
Sources
Also known as AZL-100172, BELL-CVE-2026-80928, DEBIAN-CVE-2026-80928, GHSA-pw4j-jrv7-fq3m, UBUNTU-CVE-2026-80928.