CVE-2026-98837 ALSA: caiaq: unregister the input device when probe fails
A use-after-free vulnerability in the ALSA caiaq driver allows local attackers to cause a system crash or potentially execute code by triggering a probe failure.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98837?
CVE-2026-98837 is an use after free vulnerability in Linux, published on 18 Oct 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:
ALSA: caiaq: unregister the input device when probe fails
setup_card() registers the input device, whose name and phys point into struct snd_usb_caiaqdev, and then goes on to snd_card_register() and snd_usb_caiaq_control_init(). If either fails, snd_probe() calls snd_card_free(), which frees the device state but leaves the input device registered: card_free() only clears the pointer, and the input device is unregistered from snd_disconnect() alone. Reading its "uevent" attribute afterwards dereferences freed memory:
BUG: KASAN: slab-use-after-free in string+0x4a9/0x4f0 Read of size 1 at addr ffff8880208f5043 by task caiaq/4967 add_uevent_var+0x183/0x3a0 input_dev_uevent+0x162/0x900 dev_uevent+0x2f1/0x870 uevent_show+0x1ca/0x3a0 ...
Unregister the input device on the probe error path, as snd_disconnect() does. snd_usb_caiaq_input_disconnect() is a no-op when no input device was registered.
Reproduced with a raw-gadget Audio Kontrol 1 and a temporary hack that makes snd_usb_caiaq_control_init() fail.
Which versions are affected by CVE-2026-98837?
How do I fix CVE-2026-98837?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-98837 being exploited?
There is no known exploitation of CVE-2026-98837 in the wild and no public exploit code.
Sources
Also known as AZL-108866, BELL-CVE-2026-98837, DEBIAN-CVE-2026-98837, GHSA-gvp5-mg7r-w29g, UBUNTU-CVE-2026-98837.