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VulnerabilityPublished Updated

CVE-2026-43437: Linux kernel · Use After Free

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in fc71f888994569f87d5bee20b1ac6c9c1e3a7a79 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in fc71f888994569f87d5bee20b1ac6c9c1e3a7a79, f2cb2e0d27fb925c73a78f0ce7d6dbf68d3747c1, c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ f2b3614cefb61ee6046a0aaee503ee37f227d310, < fc71f888994569f87d5bee20b1ac6c9c1e3a7a79
Fixed in
  • fc71f888994569f87d5bee20b1ac6c9c1e3a7a79
LinuxLinuxAffected
  • ≥ f2b3614cefb61ee6046a0aaee503ee37f227d310, < f2cb2e0d27fb925c73a78f0ce7d6dbf68d3747c1
Fixed in
  • f2cb2e0d27fb925c73a78f0ce7d6dbf68d3747c1
LinuxLinuxAffected
  • ≥ f2b3614cefb61ee6046a0aaee503ee37f227d310, < c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694
Fixed in
  • c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694
LinuxLinuxAffected
  • ≥ f2b3614cefb61ee6046a0aaee503ee37f227d310, < ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432
Fixed in
  • ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432
LinuxLinuxAffected
  • ≥ f2b3614cefb61ee6046a0aaee503ee37f227d310, < 629cf09464cf98670996ea5c191dc9743e6f3f00
Fixed in
  • 629cf09464cf98670996ea5c191dc9743e6f3f00
LinuxLinuxAffected
  • ≥ f2b3614cefb61ee6046a0aaee503ee37f227d310, < 9baee36e8c5443411c4629afabafaff8a46a23fd
Fixed in
  • 9baee36e8c5443411c4629afabafaff8a46a23fd

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain() In the drain loop, the local variable 'runtime' is reassigned to a linked stream's runtime (runtime = s->runtime at line 2157). After releasing the stream lock at line 2169, the code accesses runtime->no_period_wakeup, runtime->rate, and runtime->buffer_size (lines 2170-2178) — all referencing the linked stream's runtime without any lock or refcount protecting its lifetime. A concurrent close() on the linked stream's fd triggers snd_pcm_release_substream() → snd_pcm_drop() → pcm_release_private() → snd_pcm_unlink() → snd_pcm_detach_substream() → kfree(runtime). No synchronization prevents kfree(runtime) from completing while the drain path dereferences the stale pointer. Fix by caching the needed runtime fields (no_period_wakeup, rate, buffer_size) into local variables while still holding the stream lock, and using the cached values after the lock is released.

References

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