CVE-2026-98742 ALSA: seq: Serialize compat port-info ioctls
A race condition in the Linux kernel ALSA sequencer allows local attackers to trigger use-after-free, potentially leading to privilege escalation or code execution.
- 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-2026-98742?
CVE-2026-98742 is a vulnerability in Linux, published on 18 Oct 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: seq: Serialize compat port-info ioctls
The native sequencer ioctl path serializes handler calls with client->ioctl_mutex, but the translated port-info compat path invokes the same handlers through snd_seq_kernel_client_ctl() without taking that mutex.
This lets concurrent compat CREATE_PORT requests pass the port-count check before any request reaches the serialized insertion. The computed integer port index can then exceed the address field range and wrap to an existing index. Subsequent subscriber teardown can resolve the duplicate address to the wrong port and access a freed subscriber.
Take ioctl_mutex while dispatching converted port-info requests, matching the native ioctl path. All translated port-info commands share this helper, so their accesses to the client port state are serialized as well.
Which versions are affected by CVE-2026-98742?
How do I fix CVE-2026-98742?
Apply the vendor's patch.
Is CVE-2026-98742 being exploited?
There is no known exploitation of CVE-2026-98742 in the wild and no public exploit code.
Sources
Also known as AZL-109013, BELL-CVE-2026-98742, DEBIAN-CVE-2026-98742, GHSA-qq2g-8h6m-jjjf, UBUNTU-CVE-2026-98742.