CVE-2026-89623 HID: mcp2221: stop device IO before hid_hw_stop
A race condition in the Linux kernel MCP2221 HID driver allows use-after-free during device removal, potentially enabling local privilege escalation or code execution.
- 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-2026-89623?
CVE-2026-89623 is an use after free vulnerability in Linux, published on 11 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:
HID: mcp2221: stop device IO before hid_hw_stop
Quiesce device IO at the start of the devm cleanup callback mcp2221_hid_unregister() so that incoming HID reports cannot race with hardware teardown during probe failure or device removal, addressing a potential use-after-free.
Guard the call to hid_device_io_stop() with io_started. On normal removal hid_device_remove() has already cleared io_started before the devres group is released, so an unconditional call would otherwise hit the !io_started path and emit a spurious "io already stopped" warning on every removal. The guard preserves the probe-failure balancing, where io_started is still set after hid_device_io_start(), while staying silent on the normal removal path.
Which versions are affected by CVE-2026-89623?
How do I fix CVE-2026-89623?
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-2026-89623 being exploited?
There is no known exploitation of CVE-2026-89623 in the wild and no public exploit code.
Sources
Also known as AZL-100487, BELL-CVE-2026-89623, DEBIAN-CVE-2026-89623, GHSA-p59v-m859-4ppq, UBUNTU-CVE-2026-89623.