ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()
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.
CVE-2026-43437
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-43437
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
"lessThan": "9baee36e8c5443411c4629afabafaff8a46a23fd",
"versionType": "git"
},
{
"status": "affected",
"version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
"lessThan": "f2cb2e0d27fb925c73a78f0ce7d6dbf68d3747c1",
"versionType": "git"
},
{
"status": "affected",
"version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
"lessThan": "fc71f888994569f87d5bee20b1ac6c9c1e3a7a79",
"versionType": "git"
},
{
"status": "affected",
"version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
"lessThan": "629cf09464cf98670996ea5c191dc9743e6f3f00",
"versionType": "git"
},
{
"status": "affected",
"version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
"lessThan": "ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432",
"versionType": "git"
},
{
"status": "affected",
"version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
"lessThan": "4a758e9a1f5ed722f83c4dd35f867fe811553bcb",
"versionType": "git"
},
{
"status": "affected",
"version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
"lessThan": "c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694",
"versionType": "git"
},
{
"status": "affected",
"version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
"lessThan": "9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6",
"versionType": "git"
}
],
"programFiles": [
"sound/core/pcm_native.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.253",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.220",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.167",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.130",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.78",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.19",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.9",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"sound/core/pcm_native.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-43437
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40075 · Revision 1
- Added to Heist Feed
- Publisher date