CVE-2026-23221 bus: fsl-mc: fix use-after-free in driver_override_show()
A race condition in the Linux kernel fsl-mc bus driver allows a use-after-free, potentially leading to code execution or system crash.
- 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-2026-23221?
CVE-2026-23221 is a high-severity use after free vulnerability in Linux kernel, published on 18 Feb 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:
bus: fsl-mc: fix use-after-free in driver_override_show()
The driver_override_show() function reads the driver_override string without holding the device_lock. However, driver_override_store() uses driver_set_override(), which modifies and frees the string while holding the device_lock.
This can result in a concurrent use-after-free if the string is freed by the store function while being read by the show function.
Fix this by holding the device_lock around the read operation.
Weakness: CWE-416
Which versions are affected by CVE-2026-23221?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-23221?
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-2026-23221 being exploited?
There is no known exploitation of CVE-2026-23221 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-77930, BELL-CVE-2026-23221, DEBIAN-CVE-2026-23221, GHSA-jp99-8xc8-367m, ROOT-OS-DEBIAN-11-CVE-2026-23221, ROOT-OS-DEBIAN-12-CVE-2026-23221 and 4 more.