Linux vulnerability

What happened

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 versions

Linux: 597603d615d2b19a9e451d8cfac24372856a522d through before 83bd62fa9620ac98d5d694bde14c50f98c8e7189 (git); 597603d615d2b19a9e451d8cfac24372856a522d through before 345c24b2bcf0923dfae1ab41497351c68214ff76 (git); 597603d615d2b19a9e451d8cfac24372856a522d through before 3727a3541788412c393eec236ad228d72efe19c7 (git); 597603d615d2b19a9e451d8cfac24372856a522d through before d258cdce50ff3e02392917258e81a0ce9555c327 (git); 597603d615d2b19a9e451d8cfac24372856a522d through before 03f52a9c170431e8f10e156b9dc0dae80b3e9198 (git); 597603d615d2b19a9e451d8cfac24372856a522d through before bdd9503c3d222d2735b56c7a8b4422ccf3de6e5c (git); 597603d615d2b19a9e451d8cfac24372856a522d through before 5d45e34bf001344e2966dabca1897561bbc9e913 (git); 597603d615d2b19a9e451d8cfac24372856a522d through before e5c33cdc6f402eab8abd36ecf436b22c9d3a8aff (git); 2.6.37 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.