CVE-2026-23191 ALSA: aloop: Fix racy access at PCM trigger
A race condition in the Linux kernel ALSA aloop driver allows local attackers to trigger a use-after-free, potentially leading to code execution or privilege escalation.
- 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-2026-23191?
CVE-2026-23191 is a high-severity use after free vulnerability in Linux kernel, published on 14 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:
ALSA: aloop: Fix racy access at PCM trigger
The PCM trigger callback of aloop driver tries to check the PCM state and stop the stream of the tied substream in the corresponding cable. Since both check and stop operations are performed outside the cable lock, this may result in UAF when a program attempts to trigger frequently while opening/closing the tied stream, as spotted by fuzzers.
For addressing the UAF, this patch changes two things: - It covers the most of code in loopback_check_format() with cable->lock spinlock, and add the proper NULL checks. This avoids already some racy accesses. - In addition, now we try to check the state of the capture PCM stream that may be stopped in this function, which was the major pain point leading to UAF.
Which versions are affected by CVE-2026-23191?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-23191?
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-2026-23191 being exploited?
There is no known exploitation of CVE-2026-23191 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-23191, DEBIAN-CVE-2026-23191, GHSA-x3gh-q355-f5px, ROOT-OS-DEBIAN-11-CVE-2026-23191, ROOT-OS-DEBIAN-12-CVE-2026-23191, ROOT-OS-DEBIAN-13-CVE-2026-23191 and 3 more.