CVE-2026-74388

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-15. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

ALSA: seq: oss: Fix UAF at handling events with embedded SysEx data

The OSS sequencer processes the input MIDI bytes into a sequencer event to be dispatched later (in snd_seq_oss_midi_putc() called from snd_seq_oss_process_event()). When it's a SysEx data, the event record contains data.ext.ptr pointer to the original SysEx bytes, and the referred data is copied into the pool afterwards at dispatching. The problem is that, if the sequencer port gets closed concurrently before the dispatch, the OSS sequencer core also releases the resources (in snd_seq_oss_midi_check_exit_port()), while the pending event may hold a stale pointer, eventually leading to a UAF at a later dispatch.

Fortunately, there is already a refcounting mechanism (snd_use_lock_t) for the OSS MIDI device access, and for addressing the issue above, we just need to extend the refcount until the event gets dispatched.

This patch extends snd_seq_oss_process_event() to give back the refcount object, which is in turn released after calling the sequencer dispatcher with the given event in the caller side.

According to the original report, KASAN report as below:

KASAN slab-use-after-free in snd_seq_event_dup+0x40c/0x470 RIP: 0033:0x7f2cb66a6340 Read of size 6 Call trace: dump_stack_lvl+0x73/0xb0 (?:?) print_report+0xd1/0x650 (?:?) srso_alias_return_thunk+0x5/0xfbef5 (?:?) __virt_addr_valid+0x1a7/0x340 (?:?) kasan_complete_mode_report_info+0x64/0x200 (?:?) kasan_report+0xf7/0x130 (?:?) snd_seq_event_dup+0x40c/0x470 (?:?) kasan_check_range+0x10c/0x1c0 (?:?) __asan_memcpy+0x27/0x70 (?:?) snd_seq_event_dup+0x9/0x470 (?:?) snd_seq_client_enqueue_event+0x139/0x240 (?:?) _raw_spin_unlock_irqrestore+0x4b/0x60 (?:?) snd_seq_kernel_client_enqueue+0x102/0x120 (?:?) snd_seq_oss_write+0x416/0x4e0 (?:?) apparmor_file_permission+0x20/0x30 (?:?) odev_write+0x3b/0x60 (?:?) vfs_write+0x1ce/0x850 (?:?) lock_release+0xc8/0x2a0 (?:?) __kasan_check_write+0x18/0x20 (?:?) __mutex_unlock_slowpath+0x129/0x510 (?:?) ksys_write+0xe1/0x180 (?:?) mutex_unlock+0x16/0x20 (?:?) odev_ioctl+0x65/0xc0 (?:?) __x64_sys_write+0x46/0x60 (?:?) x64_sys_call+0x7d/0x20d0 (?:?) do_syscall_64+0xc1/0x360 (arch/x86/entry/syscall_64.c:87) entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)

CVSS v3
7.8
EG Score
7.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 17, 2026

Advisory Details (3)

Auto-updated Aug 17, 2026
No patch confirmed yet.
generic

ALSA: seq: oss: Fix UAF at handling events with embedded SysEx data - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7c349b4f2a603202fb8c363bd2774a22ac2fddf3
generic

ALSA: seq: oss: Fix UAF at handling events with embedded SysEx data - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7aad70cabd8f34cf11a9593fcd3f2ac3f5496943
generic

ALSA: seq: oss: Fix UAF at handling events with embedded SysEx data - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6dc781778b595be94c31395b2cb167f65145d91f

Vendor Advisories for CVE-2026-74388(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 26× in last 7d / 26× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 22:56 UTCEPSS rescore
  2. 2026-08-20 21:09 UTCGHSA enrichment
  3. 2026-08-20 08:47 UTCGHSA enrichment
  4. 2026-08-19 20:25 UTCEG score recompute
  5. 2026-08-19 20:25 UTCGHSA enrichment
  6. 2026-08-19 17:04 UTCEPSS rescore
  7. 2026-08-19 08:03 UTCGHSA enrichment
  8. 2026-08-18 19:40 UTCGHSA enrichment
  9. 2026-08-18 07:18 UTCGHSA enrichment
  10. 2026-08-17 18:57 UTCEG score recompute
  11. 2026-08-17 18:56 UTCGHSA enrichment
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-17 06:26 UTCEG score recompute
  14. 2026-08-17 06:26 UTCGHSA enrichment
  15. 2026-08-17 05:56 UTCEG score recompute▲ 7.80
  16. 2026-08-17 05:56 UTCGHSA enrichment
  17. 2026-08-17 05:54 UTCMITRE cvelistV5CVSS v3 → 7.8 · severity → HIGH
  18. 2026-08-17 05:26 UTCEG score recompute
  19. 2026-08-17 05:26 UTCGHSA enrichment
  20. 2026-08-17 05:24 UTCMITRE cvelistV5
  21. 2026-08-16 14:56 UTCEPSS rescore
  22. 2026-08-16 14:56 UTCEPSS rescore
  23. 2026-08-16 02:15 UTCEPSS rescore
  24. 2026-08-15 06:23 UTCNVD update
  25. 2026-08-15 06:14 UTCEG score recompute
Show 1 more
  1. 2026-08-15 06:12 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-74388?
CVE-2026-74388 is a high vulnerability published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: oss: Fix UAF at handling events with embedded SysEx data The OSS sequencer processes the input MIDI bytes into a sequencer event to be dispatched later (in sndseqossmidiputc() called from sndseqossprocessevent()). When…
When was CVE-2026-74388 disclosed?
CVE-2026-74388 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74388 actively exploited?
CVE-2026-74388 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.5% of all scored CVEs.
What is the CVSS score of CVE-2026-74388?
CVE-2026-74388 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-74388?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-74388, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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