Bug 2424937 (CVE-2023-54022)

Summary: CVE-2023-54022 kernel: Linux kernel ALSA USB audio: Denial of Service due to memory leaks in MIDI 2.0 / UMP device handling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the Linux kernel's Advanced Linux Sound Architecture (ALSA) USB audio driver. This vulnerability, related to improper memory management when handling MIDI 2.0 / Universal MIDI Packet (UMP) devices, could lead to memory leaks. A local attacker with low privileges could exploit this flaw by triggering specific allocation and initialization errors. This could result in a Denial of Service (DoS) due to resource exhaustion.
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Description OSIDB Bzimport 2025-12-24 12:01:59 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ALSA: usb-audio: Fix potential memory leaks at error path for UMP open

The allocation and initialization errors at alloc_midi_urbs() that is
called at MIDI 2.0 / UMP device are supposed to be handled at the
caller side by invoking free_midi_urbs().  However, free_midi_urbs()
loops only for ep->num_urbs entries, and since ep->num_entries wasn't
updated yet at the allocation / init error in alloc_midi_urbs(), this
entry won't be released.

The intention of free_midi_urbs() is to release the whole elements, so
change the loop size to NUM_URBS to scan over all elements for fixing
the missed releases.

Also, the call of free_midi_urbs() is missing at
snd_usb_midi_v2_open().  Although it'll be released later at
reopen/close or disconnection, it's better to release immediately at
the error path.
Comment 1 Alexander B 2025-12-25 14:35:02 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025122434-CVE-2023-54022-ae26@gregkh/T