CVE-2026-98742

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.