CVE-2026-23191High· 7.8▾ Twilight

ALSA: aloop: Fix racy access at PCM trigger

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 corr…

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score43/ 100 · Moderate

impact 42.9 · likelihood 0 · exploitation 0

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Proof of concept

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Published

Feb 14, 2026

Updated

Oct 19, 2026

CVSS

7.8

Vendor

Linux

Product

Linux

CWE

—

Depth score

43 · Moderate

EPSS

0.13% · p3

Platforms

—

Source

CVEORG

Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

decided 2026-06-16

Exploitation: none
Automatable: no
Technical impact: total

Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.

EPSS history

Exploit-prediction probability, daily snapshots since Sep 14.

0.1% → 0.1%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

4 events · 247 days

Feb 14, 2026Published
Disclosed via CVEORG
Sep 14, 2026EPSS first tracked
0.1%
Oct 14, 2026EPSS peak
0.1% → 0.1%
Oct 19, 2026Record revised
Last analysed / modified upstream

Linux #cve.org

Affected

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < f57467114f40c5aacebbea96fb4ff9e5cd2b7f18
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < c99be0d5af02adebe9cb6f9869d20397fa9935a3
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < f3ce8be893726899e3053cf8059ecc95d8410359
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 0e6245b2424d126ac90018142d09f0707e12998b
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < bad15420050db1803767e58756114800cce91ea4
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 5727ccf9d19ca414cb76d9b647883822e2789c2e
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 826af7fa62e347464b1b4e0ba2fe19a92438084f
Linux 2.6.37

Full technical detail▾

Overview

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.

Affected

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < f57467114f40c5aacebbea96fb4ff9e5cd2b7f18
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < c99be0d5af02adebe9cb6f9869d20397fa9935a3
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < f3ce8be893726899e3053cf8059ecc95d8410359
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 0e6245b2424d126ac90018142d09f0707e12998b
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < bad15420050db1803767e58756114800cce91ea4
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 5727ccf9d19ca414cb76d9b647883822e2789c2e
Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 826af7fa62e347464b1b4e0ba2fe19a92438084f
Linux 2.6.37

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

References

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#cve.org

ALSA: aloop: Fix racy access at PCM trigger

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score43/ 100 · Moderate

impact 42.9 · likelihood 0 · exploitation 0

Overview

In the Linux kernel, the following vulnerability has been resolved:

ALSA: aloop: Fix racy access at PCM trigger

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.

Affected

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < f57467114f40c5aacebbea96fb4ff9e5cd2b7f18

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < c99be0d5af02adebe9cb6f9869d20397fa9935a3

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < f3ce8be893726899e3053cf8059ecc95d8410359

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 0e6245b2424d126ac90018142d09f0707e12998b

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < bad15420050db1803767e58756114800cce91ea4

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 5727ccf9d19ca414cb76d9b647883822e2789c2e

Linux >= b1c73fc8e697eb73e23603e465e9af2711ed4183 < 826af7fa62e347464b1b4e0ba2fe19a92438084f

Linux 2.6.37