{"id":"CVE-2026-90207","published":"2026-09-17T17:17:15.813","lastModified":"2026-09-18T18:17:46.560","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: midi: Serialize input teardown with event_input\n\nsnd_midi_input_event() must not be running while a rawmidi substream is\nclosing, since this can lead to the trigger state becoming out-of-step\nthrough this sequence in snd_rawmidi_input_trigger():\n\n\tsnd_rawmidi_input_trigger(up=0)\n\t\t\t\t\tsnd_midi_input_event()\n\t\t\t\t\t -> snd_rawmidi_kernel_read()\n\t\t\t\t\t     -> snd_rawmidi_input_trigger(up=1)\n\t  -> cancel_work_sync()\n\nwhich ends with the underlying device being active unexpectedly.\n\nWhen this is called from close_substream(), further input can re-trigger\nthe input event leaving it running after rawmidi_release_priv() has set\nrfile->rmidi to NULL which leads to:\n\n\tUnable to handle kernel NULL pointer dereference at virtual address 00000000000000b0\n\tCall trace:\n\t snd_midi_input_event+0x3c/0x134 [snd_seq_midi] (P)\n\t snd_rawmidi_input_event_work+0x1c/0x2c\n\t process_one_work+0x150/0x3a4\n\t worker_thread+0x190/0x318\n\nApply a similar approach to commit ef7607ab1c8ad (\"ALSA: seq: midi:\nSerialize output teardown with event_input\") which fixed the same issue\nin the output direction, but updated to use RCU following Takashi Iwai's\nproposed follow-on patch [1].\n\nWith this change in place, midisynth_unsubscribe() clears the input file\nso snd_midi_input_event() will not re-trigger the stream and will be\nquiesced by the cancel_work_sync() in snd_rawmidi_input_trigger().\n\n[1] https://lore.kernel.org/linux-sound/20260813144224.753399-1-tiwai@suse.de/","cvssScore":7.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/210c193a9ef1312fab153948c6928e4cfaa1f03b","tags":[]},{"url":"https://git.kernel.org/stable/c/282a3ef9e4b63b2f6823bbbb3c1a90b002cdaf12","tags":[]},{"url":"https://git.kernel.org/stable/c/403f7f3ad3808a0096d84cf228fab68dc253fd9d","tags":[]},{"url":"https://git.kernel.org/stable/c/6290afaae54c7a9fa3bca3b4d5433e6d83e8669d","tags":[]},{"url":"https://git.kernel.org/stable/c/89d986897aff7275b42e075e556731b8353366af","tags":[]},{"url":"https://git.kernel.org/stable/c/de76a2b47582cd6dba2e15f024681bf377ecc94a","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}