CVE-2026-93091 firmware: arm_scmi: Quiesce notifications before teardown
A use-after-free vulnerability in the Linux kernel's SCMI driver allows local attackers to cause denial of service or execute code during device teardown.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93091?
CVE-2026-93091 is an use after free vulnerability in Linux, published on 17 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:
firmware: arm_scmi: Quiesce notifications before teardown
scmi_notification_exit() clears and releases the notification instance, but transport callbacks can still deliver incoming notifications until the TX/RX channels are freed. During remove, an RX interrupt in that window can enter scmi_notify() while notification state is being torn down and then dereference freed memory. The same ordering exists on the probe error path after notification initialization.
The notification late-init worker has a separate lifetime issue: protocol event registration queues ni->init_work on the system workqueue, so destroying ni->notify_wq does not drain that work. If the devres group is released while init_work is still pending or running, the late-init worker can dereference the freed notification instance.
Quiesce the notification core before TX/RX channels are torn down, then clean up the channels before releasing the notification core resources. Use disable_work_sync() so future late-init queueing is rejected and any already queued or running late-init work has completed before channel teardown starts.
Which versions are affected by CVE-2026-93091?
How do I fix CVE-2026-93091?
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-2026-93091 being exploited?
There is no known exploitation of CVE-2026-93091 in the wild and no public exploit code.
Sources
Also known as AZL-102393, BELL-CVE-2026-93091, DEBIAN-CVE-2026-93091, GHSA-634x-xgvq-4p3j, UBUNTU-CVE-2026-93091.