CVE-2026-93056 usb: gadget: f_uac1_legacy: remove broken string configfs attributes
A null pointer dereference in the Linux kernel's legacy USB audio gadget driver can cause a system crash when specific configfs attributes are written to.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93056?
CVE-2026-93056 is a vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_uac1_legacy: remove broken string configfs attributes
The UAC1_STR_ATTRIBUTE macro defines configfs show/store handlers for the fn_play, fn_cap, and fn_cntl string options. The store function contains an inverted null check on the kstrndup() return value.
This means every write attempt returns -ENOMEM on success and dereferences a NULL pointer on allocation failure. The attributes have been broken and unused for many years.
Remove the UAC1_STR_ATTRIBUTE macro and the three attributes it generated. The internal defaults (FILE_PCM_PLAYBACK, FILE_PCM_CAPTURE, FILE_CONTROL) set in f_audio_alloc_inst() are unaffected.
Which versions are affected by CVE-2026-93056?
How do I fix CVE-2026-93056?
Apply the vendor's patch.
Is CVE-2026-93056 being exploited?
There is no known exploitation of CVE-2026-93056 in the wild and no public exploit code.
Sources
Also known as AZL-102638, BELL-CVE-2026-93056, DEBIAN-CVE-2026-93056, GHSA-chwv-5hpv-rv25, UBUNTU-CVE-2026-93056.