The ALSA subsystem in the Linux kernel contains an event handling path that snapshots the output file pointer and then passes the underlying substream to audio write functions without proper synchronization. When a concurrent teardown releases the same raw MIDI file, the event path may subsequently reference a freed or NULL runtime buffer, resulting in a NULL dereference or use‑after‑free. This defect can crash the kernel and, depending on kernel configuration and the context of the attacker, could be leveraged for privilege escalation or denial of service. The weakness is a classic use‑after‑free scenario, as the code re‑uses an object after it has been released or invalidated.

All Linux kernel builds that expose the ALSA sequencer MIDI event processing without the recent patch commits, regardless of distribution. The vulnerability is present prior to the kernel updates that incorporate the synchronization changes described in the source commits cited in the references.

The CVSS score of 7.8 indicates high severity, and the nature of the flaw—an unchecked use‑after‑free in kernel mode—implies a high impact if successfully exploited. The EPSS score of < 1% indicates that the probability of exploitation is very low, and the vulnerability is not listed in CISA KEV. The likely attack vector is local: a user with permission to send sequencer MIDI events can trigger the flaw. Exploitability requires the ability to interact with the ALSA subsystem, so users with a console or device capable of generating MIDI events are sufficient. Because the exploit can cause a kernel panic, impacted systems may experience service disruption or unauthorized elevation of privilege.