Bug 2451189 (CVE-2026-23318)

Summary: CVE-2026-23318 kernel: ALSA: usb-audio: Use correct version for UAC3 header validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's ALSA (Advanced Linux Sound Architecture) USB audio driver. A malicious USB Audio Class 3 (UAC3) device could exploit an incorrect protocol version used for UAC3 header validation. This error causes the device's header descriptors to bypass validation, allowing a truncated UAC3 header to trigger out-of-bounds reads when the driver processes unvalidated descriptor fields.
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Description OSIDB Bzimport 2026-03-25 11:03:41 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ALSA: usb-audio: Use correct version for UAC3 header validation

The entry of the validators table for UAC3 AC header descriptor is
defined with the wrong protocol version UAC_VERSION_2, while it should
have been UAC_VERSION_3.  This results in the validator never matching
for actual UAC3 devices (protocol == UAC_VERSION_3), causing their
header descriptors to bypass validation entirely.  A malicious USB
device presenting a truncated UAC3 header could exploit this to cause
out-of-bounds reads when the driver later accesses unvalidated
descriptor fields.

The bug was introduced in the same commit as the recently fixed UAC3
feature unit sub-type typo, and appears to be from the same copy-paste
error when the UAC3 section was created from the UAC2 section.
Comment 1 Alexander B 2026-03-25 17:16:41 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026032530-CVE-2026-23318-bef0@gregkh/T