CVE Catalog

CVE-2026-90207

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.16%

6th percentile - higher than 6% of all known CVEs

Summary

A vulnerability in the Linux kernel's ALSA sequencer MIDI rawmidi input teardown involves a race condition during rawmidi substream closing. The snd_midi_input_event() function may run concurrently with the closing, leading to a NULL pointer dereference and kernel crash. The issue is fixed by serializing the teardown with event_input using RCU.

Risk Assessment

The risk is that a local user or process using ALSA MIDI could trigger a kernel panic, causing a denial of service on the system.

Recommendation

Apply the Linux kernel patch that serializes rawmidi MIDI input teardown with event_input, as described in the kernel mailing list. Update to a kernel version that includes this fix.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: midi: Serialize input teardown with event_input snd_midi_input_event() must not be running while a rawmidi substream is closing, since this can lead to the trigger state becoming out-of-step through this sequence in snd_rawmidi_input_trigger(): snd_rawmidi_input_trigger(up=0) snd_midi_input_event() -> snd_rawmidi_kernel_read() -> snd_rawmidi_input_trigger(up=1) -> cancel_work_sync() which ends with the underlying device being active unexpectedly. When this is called from close_substream(), further input can re-trigger the input event leaving it running after rawmidi_release_priv() has set rfile->rmidi to NULL which leads to: Unable to handle kernel NULL pointer dereference at virtual address 00000000000000b0 Call trace: snd_midi_input_event+0x3c/0x134 [snd_seq_midi] (P) snd_rawmidi_input_event_work+0x1c/0x2c process_one_work+0x150/0x3a4 worker_thread+0x190/0x318 Apply a similar approach to commit ef7607ab1c8ad ("ALSA: seq: midi: Serialize output teardown with event_input") which fixed the same issue in the output direction, but updated to use RCU following Takashi Iwai's proposed follow-on patch [1]. With this change in place, midisynth_unsubscribe() clears the input file so snd_midi_input_event() will not re-trigger the stream and will be quiesced by the cancel_work_sync() in snd_rawmidi_input_trigger(). [1] https://lore.kernel.org/linux-sound/[email protected]/

Vulnerability data from NVD (NIST) · CISA KEV · EPSS