CVE-2026-43437: Linux kernel · Use After Free
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 8 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
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
- git.kernel.org/stable/c/9baee36e8c5443411c4629afabafaff8a46a23fd (opens in a new tab)
- git.kernel.org/stable/c/f2cb2e0d27fb925c73a78f0ce7d6dbf68d3747c1 (opens in a new tab)
- git.kernel.org/stable/c/fc71f888994569f87d5bee20b1ac6c9c1e3a7a79 (opens in a new tab)
- git.kernel.org/stable/c/629cf09464cf98670996ea5c191dc9743e6f3f00 (opens in a new tab)
- git.kernel.org/stable/c/ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432 (opens in a new tab)
- git.kernel.org/stable/c/4a758e9a1f5ed722f83c4dd35f867fe811553bcb (opens in a new tab)
- git.kernel.org/stable/c/c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694 (opens in a new tab)
- git.kernel.org/stable/c/9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6 (opens in a new tab)