{"id":"CVE-2026-43437","summary":"ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()\n\nIn the drain loop, the local variable 'runtime' is reassigned to a\nlinked stream's runtime (runtime = s-\u003eruntime at line 2157).  After\nreleasing the stream lock at line 2169, the code accesses\nruntime-\u003eno_period_wakeup, runtime-\u003erate, and runtime-\u003ebuffer_size\n(lines 2170-2178) — all referencing the linked stream's runtime without\nany lock or refcount protecting its lifetime.\n\nA concurrent close() on the linked stream's fd triggers\nsnd_pcm_release_substream() → snd_pcm_drop() → pcm_release_private()\n→ snd_pcm_unlink() → snd_pcm_detach_substream() → kfree(runtime).\nNo synchronization prevents kfree(runtime) from completing while the\ndrain path dereferences the stale pointer.\n\nFix by caching the needed runtime fields (no_period_wakeup, rate,\nbuffer_size) into local variables while still holding the stream lock,\nand using the cached values after the lock is released.","modified":"2026-06-03T18:29:16.992929488Z","published":"2026-05-08T14:22:07.314Z","related":["SUSE-SU-2026:2068-1","SUSE-SU-2026:2111-1","SUSE-SU-2026:21876-1","SUSE-SU-2026:21877-1","SUSE-SU-2026:21916-1","SUSE-SU-2026:21919-1","SUSE-SU-2026:2195-1","SUSE-SU-2026:2202-1","SUSE-SU-2026:2215-1","SUSE-SU-2026:2216-1","SUSE-SU-2026:2217-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43437.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4a758e9a1f5ed722f83c4dd35f867fe811553bcb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/629cf09464cf98670996ea5c191dc9743e6f3f00"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9baee36e8c5443411c4629afabafaff8a46a23fd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fc71f888994569f87d5bee20b1ac6c9c1e3a7a79"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43437.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43437"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f2b3614cefb61ee6046a0aaee503ee37f227d310"},{"fixed":"9baee36e8c5443411c4629afabafaff8a46a23fd"},{"fixed":"fc71f888994569f87d5bee20b1ac6c9c1e3a7a79"},{"fixed":"629cf09464cf98670996ea5c191dc9743e6f3f00"},{"fixed":"ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432"},{"fixed":"4a758e9a1f5ed722f83c4dd35f867fe811553bcb"},{"fixed":"c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694"},{"fixed":"9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-43437.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.0.0"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"6.1.167"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.130"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.19"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-43437.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}