CVE-2026-68201

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ALSA: timer: drain a slave's callback before its master detaches it

snd_timer_close_locked() drains the closing instance's own in-flight

callback (IFLG_CALLBACK) before freeing it, but not its slaves'. When a

master instance is closed, remove_slave_links() clears each slave's

->timer; the slave's own close then reads timer == NULL and takes the

branch that skips the drain entirely (snd_timer_stop_slave() also no-ops

on a NULL timer). So a slave whose callback is still running when the

master is closed is freed underneath the live callback, leading to

use-after-free.

Drain the slaves too before remove_slave_links() severs them.

snd_timer_stop() has already taken this instance off the active list, so

no new slave callback can be queued. Take the slaves off the ack list so

a pending one can't fire either, then wait for any that is already in

flight.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References