CVE-2026-74501 ALSA: usb-audio: fix use-after-free in ump_to_endpoint()
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-74501?
CVE-2026-74501 is a vulnerability in Linux, published on 15 Aug 2026.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: fix use-after-free in ump_to_endpoint()
create_midi2_ump() registers a card-owned snd_ump_endpoint and stores a back-pointer to its per-interface snd_usb_midi2_ump object in ump->private_data, but it never installs an ump->private_free hook and never clears that pointer.
If a later step of snd_usb_midi_v2_create() fails, its error path calls free_all_midi2_umps(), which kfree()s the snd_usb_midi2_ump object while the already-registered endpoint keeps pointing at it. The created /dev/snd/umpC*D* node stays exposed, so the first operation of any UMP open, ump_to_endpoint(), dereferences the dangling ump->private_data and reads rmidi->eps[dir] out of freed memory.
A malicious USB MIDI 2.0 device that makes creation fail after the endpoint is registered can thus trigger a slab use-after-free read on a subsequent open of the UMP node.
Clear the endpoint's back-pointer before freeing the object, and let ump_to_endpoint() tolerate a NULL private_data so the open/close/trigger callbacks fail cleanly (their callers already handle a NULL endpoint) instead of dereferencing a stale pointer.
Discovered by XBOW, triaged by Baul Lee <[email protected]>
Which versions are affected by CVE-2026-74501?
How do I fix CVE-2026-74501?
Upgrade to a fixed version.
Is CVE-2026-74501 being exploited?
There is no known exploitation of CVE-2026-74501 in the wild and no public exploit code.
Sources
Also known as AZL-96105, BELL-CVE-2026-74501, DEBIAN-CVE-2026-74501, GHSA-jc2g-jx97-4cg9, UBUNTU-CVE-2026-74501.