Answer in brief
CVE-2026-74387 records a High severity (CVSS 7.8) vulnerability in ALSA: seq: midi: Serialize output teardown with event_input. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f5d470b808bc01f70978e22e595c6f7768313406 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <936641af564c3d92721704b781e36aaf223efdd2 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <718f6a56b40875f19e6915799044a02df9abfd52 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <11165fe2c5ea0516debe486d91df67abbe36905e || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d6fd2afb137f52bf00c5210cc44d08ed54dcffb4 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ef7607ab1c8adc6258fb1b27d08e26aecdc18a58 | f5d470b808bc01f70978e22e595c6f7768313406, 936641af564c3d92721704b781e36aaf223efdd2, 718f6a56b40875f19e6915799044a02df9abfd52, 11165fe2c5ea0516debe486d91df67abbe36905e, d6fd2afb137f52bf00c5210cc44d08ed54dcffb4, ef7607ab1c8adc6258fb1b27d08e26aecdc18a58 |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 15, 2026
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: midi: Serialize output teardown with event_input event_process_midi() borrows msynth->output_rfile.output and then passes the substream to dump_midi() and snd_rawmidi_kernel_write() without synchronizing with the output open/close transition. midisynth_use() also publishes output_rfile before snd_rawmidi_output_params() has finished. The last midisynth_unuse() can therefore release the same rawmidi file and free substream->runtime before snd_rawmidi_kernel_write1() takes its runtime buffer reference. That leaves the event_input path using a stale substream or runtime and can end in a NULL-deref or use-after-free. Fix this with two pieces of synchronization. Keep a short IRQ-safe spinlock only for publishing or clearing output_rfile and for pairing the output snapshot with an snd_use_lock_t reference. Once event_process_midi() has taken that in-flight reference, it drops the spinlock before calling snd_seq_dump_var_event(), dump_midi(), or snd_rawmidi_kernel_write(). midisynth_unuse() now detaches the visible rawmidi file under the same spinlock, waits for the in-flight writers to drain, and only then drains and releases the saved file. midisynth_use() likewise opens into a local snd_rawmidi_file and publishes it only after snd_rawmidi_output_params() succeeds. The buggy scenario involves two paths, with each column showing the order within that path: event_input path: last unuse path: 1. event_process_midi() snapshots 1. midisynth_unuse() starts output_rfile.output. tearing down output_rfile. 2. dump_midi() reaches 2. snd_rawmidi_kernel_release() snd_rawmidi_kernel_write() closes the output file. before runtime is pinned. 3. close_substream() frees 3. The callback keeps using substream->runtime. the borrowed substream. Validation reproduced this kernel report: KASAN null-ptr-deref in snd_rawmidi_kernel_write1+0x56/0x360 RIP: 0033:0x7fde7dd0837f RIP: 0010:snd_rawmidi_kernel_write1+0x56/0x360
Quoted source text, attributed separately from HOL analysis.