CVE-2026-68201
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
In the Linux kernel, in the ALSA timer subsystem, there is an issue with draining slave callbacks before the master detaches them. When a master instance is closed, remove_slave_links() clears each slave's ->timer, and the slave's own close then skips the drain entirely, which can lead to use-after-free if the slave's callback is still running.
Risk Assessment
This can lead to use-after-free, potentially resulting in system crashes or potential execution of malicious code by a local user.
Recommendation
Apply the Linux kernel patch that drains slave callbacks before remove_slave_links() severs them to prevent use-after-free.
Original NVD description (English source)
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.