CVE-2026-89737 usb: typec: thunderbolt: Disable work before freeing tbt on remove
A use-after-free vulnerability in the Linux kernel's Thunderbolt USB Type-C driver allows local attackers to cause a system crash or potentially execute code during device removal.
- 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-2026-89737?
CVE-2026-89737 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:
usb: typec: thunderbolt: Disable work before freeing tbt on remove
tbt_altmode_remove() drops the plug and cable references without draining tbt->work. The work function dereferences those references, and can also requeue itself in its error path. The VDM callbacks can queue the same work item.
Disable and drain tbt->work before dropping the references. This waits for an existing invocation and prevents subsequent schedule_work() calls from queueing it during teardown.
This issue was found by an in-house static analysis tool and confirmed by manual code review.
Which versions are affected by CVE-2026-89737?
How do I fix CVE-2026-89737?
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-2026-89737 being exploited?
There is no known exploitation of CVE-2026-89737 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-89737, DEBIAN-CVE-2026-89737, GHSA-vj4x-g937-4233, UBUNTU-CVE-2026-89737.