CVE-2026-23191
Unknown Unknown - Not Provided
Use-After-Free Vulnerability in Linux ALSA aloop PCM Trigger

Publication date: 2026-02-14

Last updated on: 2026-04-03

Assigner: kernel.org

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.
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Meta Information
Published
2026-02-14
Last Modified
2026-04-03
Generated
2026-05-07
AI Q&A
2026-02-14
EPSS Evaluated
2026-05-05
NVD
CVE-2026-23191
EUVD
EUVD-2026-6109
Affected Vendors & Products
Showing 10 associated CPEs
Vendor Product Version / Range
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel From 6.13 (inc) to 6.18.10 (exc)
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel From 2.6.37 (inc) to 6.12.70 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the Linux kernel's ALSA aloop driver, specifically in the PCM trigger callback. The issue arises because the code checks the PCM state and stops the tied substream's stream outside of the cable lock, which can cause a use-after-free (UAF) condition. This happens when a program frequently triggers the stream while opening or closing the tied stream, leading to race conditions.

The fix involves two main changes: first, most of the code in loopback_check_format() is now protected by the cable's spinlock and includes proper NULL checks to prevent some race conditions. Second, the state of the capture PCM stream is checked more carefully to avoid the main cause of the UAF.


How can this vulnerability impact me? :

This vulnerability can lead to a use-after-free condition in the ALSA aloop driver of the Linux kernel. Exploiting this could cause system instability, crashes, or potentially allow an attacker to execute arbitrary code or escalate privileges by triggering the race condition during frequent opening and closing of audio streams.


How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

I don't know


How can this vulnerability be detected on my network or system? Can you suggest some commands?

I don't know


What immediate steps should I take to mitigate this vulnerability?

I don't know


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