CVE-2026-46090: ALSA: aloop: Fix peer runtime UAF during format-change stop

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-10-19
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: aloop: Fix peer runtime UAF during format-change stop loopback_check_format() may stop the capture side when playback starts with parameters that no longer match a running capture stream. Commit 826af7fa62e3 ("ALSA: aloop: Fix racy access at PCM trigger") moved the peer lookup under cable->lock, but the actual snd_pcm_stop() still runs after dropping that lock. A concurrent close can clear the capture entry from cable->streams[] and detach or free its runtime while the playback trigger path still holds a stale peer substream pointer. Keep a per-cable count of in-flight peer stops before dropping cable->lock, and make free_cable() wait for those stops before detaching the runtime. This preserves the existing behavior while making the peer runtime lifetime explicit.

Affected products

Linux kernel: from 2.6.37 before 5.10.259; from 5.11 before 5.15.210; from 5.16 before 6.12.88; from 6.13 before 6.18.27; from 6.19 before 7.0.4; 7.1-rc1 — fixed in 5.10.259, 5.15.210, 6.12.88, 6.18.27, 7.0.4

How to fix

Upgrade to a fixed version: Linux kernel 5.10.259, 5.15.210, 6.12.88, 6.18.27. Check the vendor advisory for mitigations.

References

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