CVE-2026-74387

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74387", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.890Z", "datePublished": "2026-08-15T05:59:02.457Z", "dateUpdated": "2026-10-16T18:55:36.992Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:46:36.550Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: midi: Serialize output teardown with event_input\n\nevent_process_midi() borrows msynth->output_rfile.output and then\npasses the substream to dump_midi() and snd_rawmidi_kernel_write()\nwithout synchronizing with the output open/close transition.\nmidisynth_use() also publishes output_rfile before\nsnd_rawmidi_output_params() has finished.\n\nThe last midisynth_unuse() can therefore release the same rawmidi file\nand free substream->runtime before snd_rawmidi_kernel_write1() takes\nits runtime buffer reference. That leaves the event_input path using a\nstale substream or runtime and can end in a NULL-deref or use-after-free.\n\nFix this with two pieces of synchronization. Keep a short IRQ-safe\nspinlock only for publishing or clearing output_rfile and for pairing\nthe output snapshot with an snd_use_lock_t reference. Once\nevent_process_midi() has taken that in-flight reference, it drops the\nspinlock before calling snd_seq_dump_var_event(), dump_midi(), or\nsnd_rawmidi_kernel_write(). midisynth_unuse() now detaches the visible\nrawmidi file under the same spinlock, waits for the in-flight writers\nto drain, and only then drains and releases the saved file.\nmidisynth_use() likewise opens into a local snd_rawmidi_file and\npublishes it only after snd_rawmidi_output_params() succeeds.\n\nThe buggy scenario involves two paths, with each column showing the\norder within that path:\n\nevent_input path: last unuse path:\n1. event_process_midi() snapshots 1. midisynth_unuse() starts\n output_rfile.output. tearing down output_rfile.\n2. dump_midi() reaches 2. snd_rawmidi_kernel_release()\n snd_rawmidi_kernel_write() closes the output file.\n before runtime is pinned. 3. close_substream() frees\n3. The callback keeps using substream->runtime.\n the borrowed substream.\n\nValidation reproduced this kernel report:\nKASAN null-ptr-deref in snd_rawmidi_kernel_write1+0x56/0x360\nRIP: 0033:0x7fde7dd0837f\nRIP: 0010:snd_rawmidi_kernel_write1+0x56/0x360"}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The bug is reached only via local ALSA sequencer interfaces: opening /dev/snd/seq, subscribing to a MIDI synth port (SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT), writing events (snd_seq_write), and unsubscribing (SNDRV_SEQ_IOCTL_UNSUBSCRIBE_PORT). There is no network, Bluetooth, or physical-device packet path to event_process_midi().\nAC:L - Exploitation is a race between MIDI event delivery and the last midisynth_unuse() teardown; an attacker controls both sides by concurrently writing sequencer events and unsubscribing from the same MIDI output port. Published reproducers triggered KASAN null-deref/UAF reliably without external timing luck.\nPR:L - Any unprivileged local user with standard ALSA access (typically membership in the audio group for /dev/snd/seq) can create a sequencer client, subscribe to hardware MIDI synth ports, dispatch events, and trigger teardown. No real root/CAP_SYS_ADMIN or user-namespace capability is required.\nUI:N - Exploitation requires no victim interaction; the attacker programmatically opens the sequencer, subscribes, floods MIDI events, and unsubscribes from their own client. No mount, file open, or other user-driven action by another party is needed.\nS:U - Impact is kernel memory corruption and potential local privilege escalation within the same kernel security domain. It does not cross a VM/host, IOMMU, or sandbox boundary; compromised resources remain under the same OS authority.\nC:H - The race frees substream->runtime (kmalloc-192 snd_rawmidi_runtime) while event_process_midi() still dereferences it in dump_midi()/snd_rawmidi_kernel_write1(), producing a confirmed slab use-after-free and NULL-deref. UAF on kernel heap objects enables arbitrary memory disclosure via heap grooming.\nI:H - Use-after-free of the rawmidi runtime while the write path accesses runtime->buffer and related fields can be turned into controlled heap corruption and arbitrary kernel writes/code execution, not merely a one-shot crash. Memory corruption primitives warrant High integrity impact.\nA:H - Concurrent unsubscribe frees the output runtime during an in-flight write, causing KASAN-reported null-pointer dereference and slab use-after-free in snd_rawmidi_kernel_write1(). This can oops or panic the kernel and be retriggered by repeated subscribe/write/unsubscribe cycles."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["sound/core/seq/seq_midi.c"], "versions": [{"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "f5d470b808bc01f70978e22e595c6f7768313406", "status": "affected", "versionType": "git"}, {"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "936641af564c3d92721704b781e36aaf223efdd2", "status": "affected", "versionType": "git"}, {"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "718f6a56b40875f19e6915799044a02df9abfd52", "status": "affected", "versionType": "git"}, {"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "11165fe2c5ea0516debe486d91df67abbe36905e", "status": "affected", "versionType": "git"}, {"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "d6fd2afb137f52bf00c5210cc44d08ed54dcffb4", "status": "affected", "versionType": "git"}, {"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "ef7607ab1c8adc6258fb1b27d08e26aecdc18a58", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["sound/core/seq/seq_midi.c"], "versions": [{"version": "2.6.12", "status": "affected"}, {"version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.1.178"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.145"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.97"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.18.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/f5d470b808bc01f70978e22e595c6f7768313406"}, {"url": "https://git.kernel.org/stable/c/936641af564c3d92721704b781e36aaf223efdd2"}, {"url": "https://git.kernel.org/stable/c/718f6a56b40875f19e6915799044a02df9abfd52"}, {"url": "https://git.kernel.org/stable/c/11165fe2c5ea0516debe486d91df67abbe36905e"}, {"url": "https://git.kernel.org/stable/c/d6fd2afb137f52bf00c5210cc44d08ed54dcffb4"}, {"url": "https://git.kernel.org/stable/c/ef7607ab1c8adc6258fb1b27d08e26aecdc18a58"}], "title": "ALSA: seq: midi: Serialize output teardown with event_input", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-74387", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T18:55:07.666798Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T18:55:36.992Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-74387", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T18:55:07.666798Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T18:55:08.571Z"}}], "cna": {"title": "ALSA: seq: midi: Serialize output teardown with event_input", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:L - The bug is reached only via local ALSA sequencer interfaces: opening /dev/snd/seq, subscribing to a MIDI synth port (SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT), writing events (snd_seq_write), and unsubscribing (SNDRV_SEQ_IOCTL_UNSUBSCRIBE_PORT). There is no network, Bluetooth, or physical-device packet path to event_process_midi().\nAC:L - Exploitation is a race between MIDI event delivery and the last midisynth_unuse() teardown; an attacker controls both sides by concurrently writing sequencer events and unsubscribing from the same MIDI output port. Published reproducers triggered KASAN null-deref/UAF reliably without external timing luck.\nPR:L - Any unprivileged local user with standard ALSA access (typically membership in the audio group for /dev/snd/seq) can create a sequencer client, subscribe to hardware MIDI synth ports, dispatch events, and trigger teardown. No real root/CAP_SYS_ADMIN or user-namespace capability is required.\nUI:N - Exploitation requires no victim interaction; the attacker programmatically opens the sequencer, subscribes, floods MIDI events, and unsubscribes from their own client. No mount, file open, or other user-driven action by another party is needed.\nS:U - Impact is kernel memory corruption and potential local privilege escalation within the same kernel security domain. It does not cross a VM/host, IOMMU, or sandbox boundary; compromised resources remain under the same OS authority.\nC:H - The race frees substream->runtime (kmalloc-192 snd_rawmidi_runtime) while event_process_midi() still dereferences it in dump_midi()/snd_rawmidi_kernel_write1(), producing a confirmed slab use-after-free and NULL-deref. UAF on kernel heap objects enables arbitrary memory disclosure via heap grooming.\nI:H - Use-after-free of the rawmidi runtime while the write path accesses runtime->buffer and related fields can be turned into controlled heap corruption and arbitrary kernel writes/code execution, not merely a one-shot crash. Memory corruption primitives warrant High integrity impact.\nA:H - Concurrent unsubscribe frees the output runtime during an in-flight write, causing KASAN-reported null-pointer dereference and slab use-after-free in snd_rawmidi_kernel_write1(). This can oops or panic the kernel and be retriggered by repeated subscribe/write/unsubscribe cycles."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "f5d470b808bc01f70978e22e595c6f7768313406", "versionType": "git"}, {"status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "936641af564c3d92721704b781e36aaf223efdd2", "versionType": "git"}, {"status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "718f6a56b40875f19e6915799044a02df9abfd52", "versionType": "git"}, {"status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "11165fe2c5ea0516debe486d91df67abbe36905e", "versionType": "git"}, {"status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "d6fd2afb137f52bf00c5210cc44d08ed54dcffb4", "versionType": "git"}, {"status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "ef7607ab1c8adc6258fb1b27d08e26aecdc18a58", "versionType": "git"}], "programFiles": ["sound/core/seq/seq_midi.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "2.6.12"}, {"status": "unaffected", "version": "0", "lessThan": "2.6.12", "versionType": "semver"}, {"status": "unaffected", "version": "6.1.178", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.145", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.97", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.40", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.1.5", "versionType": "semver", "lessThanOrEqual": "7.1.*"}, {"status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["sound/core/seq/seq_midi.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/f5d470b808bc01f70978e22e595c6f7768313406"}, {"url": "https://git.kernel.org/stable/c/936641af564c3d92721704b781e36aaf223efdd2"}, {"url": "https://git.kernel.org/stable/c/718f6a56b40875f19e6915799044a02df9abfd52"}, {"url": "https://git.kernel.org/stable/c/11165fe2c5ea0516debe486d91df67abbe36905e"}, {"url": "https://git.kernel.org/stable/c/d6fd2afb137f52bf00c5210cc44d08ed54dcffb4"}, {"url": "https://git.kernel.org/stable/c/ef7607ab1c8adc6258fb1b27d08e26aecdc18a58"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: midi: Serialize output teardown with event_input\n\nevent_process_midi() borrows msynth->output_rfile.output and then\npasses the substream to dump_midi() and snd_rawmidi_kernel_write()\nwithout synchronizing with the output open/close transition.\nmidisynth_use() also publishes output_rfile before\nsnd_rawmidi_output_params() has finished.\n\nThe last midisynth_unuse() can therefore release the same rawmidi file\nand free substream->runtime before snd_rawmidi_kernel_write1() takes\nits runtime buffer reference. That leaves the event_input path using a\nstale substream or runtime and can end in a NULL-deref or use-after-free.\n\nFix this with two pieces of synchronization. Keep a short IRQ-safe\nspinlock only for publishing or clearing output_rfile and for pairing\nthe output snapshot with an snd_use_lock_t reference. Once\nevent_process_midi() has taken that in-flight reference, it drops the\nspinlock before calling snd_seq_dump_var_event(), dump_midi(), or\nsnd_rawmidi_kernel_write(). midisynth_unuse() now detaches the visible\nrawmidi file under the same spinlock, waits for the in-flight writers\nto drain, and only then drains and releases the saved file.\nmidisynth_use() likewise opens into a local snd_rawmidi_file and\npublishes it only after snd_rawmidi_output_params() succeeds.\n\nThe buggy scenario involves two paths, with each column showing the\norder within that path:\n\nevent_input path: last unuse path:\n1. event_process_midi() snapshots 1. midisynth_unuse() starts\n output_rfile.output. tearing down output_rfile.\n2. dump_midi() reaches 2. snd_rawmidi_kernel_release()\n snd_rawmidi_kernel_write() closes the output file.\n before runtime is pinned. 3. close_substream() frees\n3. The callback keeps using substream->runtime.\n the borrowed substream.\n\nValidation reproduced this kernel report:\nKASAN null-ptr-deref in snd_rawmidi_kernel_write1+0x56/0x360\nRIP: 0033:0x7fde7dd0837f\nRIP: 0010:snd_rawmidi_kernel_write1+0x56/0x360"}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.178", "versionStartIncluding": "2.6.12"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.145", "versionStartIncluding": "2.6.12"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.97", "versionStartIncluding": "2.6.12"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.40", "versionStartIncluding": "2.6.12"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.1.5", "versionStartIncluding": "2.6.12"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.2", "versionStartIncluding": "2.6.12"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:46:36.550Z"}}}, "cveMetadata": {"cveId": "CVE-2026-74387", "state": "PUBLISHED", "dateUpdated": "2026-10-16T18:55:36.992Z", "dateReserved": "2026-08-15T05:44:03.890Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-08-15T05:59:02.457Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["sound/core/seq/seq_midi.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "f5d470b808bc01f70978e22e595c6f7768313406", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}, {"lessThan": "936641af564c3d92721704b781e36aaf223efdd2", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}, {"lessThan": "718f6a56b40875f19e6915799044a02df9abfd52", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}, {"lessThan": "11165fe2c5ea0516debe486d91df67abbe36905e", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}, {"lessThan": "d6fd2afb137f52bf00c5210cc44d08ed54dcffb4", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}, {"lessThan": "ef7607ab1c8adc6258fb1b27d08e26aecdc18a58", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["sound/core/seq/seq_midi.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "2.6.12"}, {"lessThan": "2.6.12", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.178", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.145", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.97", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.40", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.5", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: midi: Serialize output teardown with event_input\n\nevent_process_midi() borrows msynth->output_rfile.output and then\npasses the substream to dump_midi() and snd_rawmidi_kernel_write()\nwithout synchronizing with the output open/close transition.\nmidisynth_use() also publishes output_rfile before\nsnd_rawmidi_output_params() has finished.\n\nThe last midisynth_unuse() can therefore release the same rawmidi file\nand free substream->runtime before snd_rawmidi_kernel_write1() takes\nits runtime buffer reference. That leaves the event_input path using a\nstale substream or runtime and can end in a NULL-deref or use-after-free.\n\nFix this with two pieces of synchronization. Keep a short IRQ-safe\nspinlock only for publishing or clearing output_rfile and for pairing\nthe output snapshot with an snd_use_lock_t reference. Once\nevent_process_midi() has taken that in-flight reference, it drops the\nspinlock before calling snd_seq_dump_var_event(), dump_midi(), or\nsnd_rawmidi_kernel_write(). midisynth_unuse() now detaches the visible\nrawmidi file under the same spinlock, waits for the in-flight writers\nto drain, and only then drains and releases the saved file.\nmidisynth_use() likewise opens into a local snd_rawmidi_file and\npublishes it only after snd_rawmidi_output_params() succeeds.\n\nThe buggy scenario involves two paths, with each column showing the\norder within that path:\n\nevent_input path: last unuse path:\n1. event_process_midi() snapshots 1. midisynth_unuse() starts\n output_rfile.output. tearing down output_rfile.\n2. dump_midi() reaches 2. snd_rawmidi_kernel_release()\n snd_rawmidi_kernel_write() closes the output file.\n before runtime is pinned. 3. close_substream() frees\n3. The callback keeps using substream->runtime.\n the borrowed substream.\n\nValidation reproduced this kernel report:\nKASAN null-ptr-deref in snd_rawmidi_kernel_write1+0x56/0x360\nRIP: 0033:0x7fde7dd0837f\nRIP: 0010:snd_rawmidi_kernel_write1+0x56/0x360"}], "id": "CVE-2026-74387", "lastModified": "2026-10-16T19:17:43.473", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-74387", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T18:55:07.666798Z", "version": "2.0.3"}}]}, "published": "2026-08-15T06:22:40.610", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/11165fe2c5ea0516debe486d91df67abbe36905e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/718f6a56b40875f19e6915799044a02df9abfd52"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/936641af564c3d92721704b781e36aaf223efdd2"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d6fd2afb137f52bf00c5210cc44d08ed54dcffb4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ef7607ab1c8adc6258fb1b27d08e26aecdc18a58"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f5d470b808bc01f70978e22e595c6f7768313406"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ALSA: seq: midi: Serialize output teardown with event_input", "id": "2516845", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2516845"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-476", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nALSA: seq: midi: Serialize output teardown with event_input\nevent_process_midi() borrows msynth->output_rfile.output and then\npasses the substream to dump_midi() and snd_rawmidi_kernel_write()\nwithout synchronizing with the output open/close transition.\nmidisynth_use() also publishes output_rfile before\nsnd_rawmidi_output_params() has finished.\nThe last midisynth_unuse() can therefore release the same rawmidi file\nand free substream->runtime before snd_rawmidi_kernel_write1() takes\nits runtime buffer reference. That leaves the event_input path using a\nstale substream or runtime and can end in a NULL-deref or use-after-free.\nFix this with two pieces of synchronization. Keep a short IRQ-safe\nspinlock only for publishing or clearing output_rfile and for pairing\nthe output snapshot with an snd_use_lock_t reference. Once\nevent_process_midi() has taken that in-flight reference, it drops the\nspinlock before calling snd_seq_dump_var_event(), dump_midi(), or\nsnd_rawmidi_kernel_write(). midisynth_unuse() now detaches the visible\nrawmidi file under the same spinlock, waits for the in-flight writers\nto drain, and only then drains and releases the saved file.\nmidisynth_use() likewise opens into a local snd_rawmidi_file and\npublishes it only after snd_rawmidi_output_params() succeeds.\nThe buggy scenario involves two paths, with each column showing the\norder within that path:\nevent_input path: last unuse path:\n1. event_process_midi() snapshots 1. midisynth_unuse() starts\noutput_rfile.output. tearing down output_rfile.\n2. dump_midi() reaches 2. snd_rawmidi_kernel_release()\nsnd_rawmidi_kernel_write() closes the output file.\nbefore runtime is pinned. 3. close_substream() frees\n3. The callback keeps using substream->runtime.\nthe borrowed substream.\nValidation reproduced this kernel report:\nKASAN null-ptr-deref in snd_rawmidi_kernel_write1+0x56/0x360\nRIP: 0033:0x7fde7dd0837f\nRIP: 0010:snd_rawmidi_kernel_write1+0x56/0x360", "A flaw was found in the Linux kernel's Advanced Linux Sound Architecture (ALSA) sequencer MIDI component. A race condition exists during the teardown of MIDI output with event input processing. This can allow a local attacker to trigger a null pointer dereference or use-after-free condition. Successful exploitation could lead to a system crash, resulting in a Denial of Service (DoS)."], "name": "CVE-2026-74387", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74387\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74387\nhttps://lore.kernel.org/linux-cve-announce/2026081506-CVE-2026-74387-2911@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1da177e4c3f41524e886b7f1b8a0c1fc7321cac2,f5d470b808bc01f70978e22e595c6f7768313406)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1da177e4c3f41524e886b7f1b8a0c1fc7321cac2,936641af564c3d92721704b781e36aaf223efdd2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1da177e4c3f41524e886b7f1b8a0c1fc7321cac2,718f6a56b40875f19e6915799044a02df9abfd52)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1da177e4c3f41524e886b7f1b8a0c1fc7321cac2,11165fe2c5ea0516debe486d91df67abbe36905e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1da177e4c3f41524e886b7f1b8a0c1fc7321cac2,d6fd2afb137f52bf00c5210cc44d08ed54dcffb4)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1da177e4c3f41524e886b7f1b8a0c1fc7321cac2,ef7607ab1c8adc6258fb1b27d08e26aecdc18a58)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "2.6.12"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,2.6.12)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.178,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.145,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.97,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.40,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.5,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-15T16:30:03.971850+00:00", "updated": "2026-08-17T14:30:06.676913+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-416", "CWE-476", "CWE-362"]}