CVE-2026-89739 usb: dwc3: gadget: Fix use-after-free in dwc3_gadget_free_endpoints due to race condition
A race condition in the Linux kernel DWC3 USB gadget driver allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.
- 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-2026-89739?
CVE-2026-89739 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: dwc3: gadget: Fix use-after-free in dwc3_gadget_free_endpoints due to race condition
In dwc3_gadget_init_endpoint, &dep->nostream_work is bound with dwc3_nostream_work, and dwc3_gadget_endpoint_stream_event can queue this delayed work on system_percpu_wq when a DEPEVT_STREAM_NOSTREAM event is received.
If we remove the gadget, dwc3_gadget_free_endpoints makes cleanup and the memory allocated for dep with kzalloc() is released by kfree(dep), while the delayed work mentioned above may still be pending or running. The sequence of operations that may lead to a UAF bug is as follows:
CPU0 CPU1
| dwc3_thread_interrupt | dwc3_endpoint_interrupt | dwc3_gadget_endpoint_stream_event | queue_delayed_work(system_percpu_wq, | &dep->nostream_work) dwc3_gadget_free_endpoints | dwc3_free_trb_pool(dep) | list_del(&dep->endpoint.ep_list) | dwc3_debugfs_remove_endpoint_dir(dep) | kfree(dep) | // dep is freed | | dwc3_nostream_work | // use dep (use-after-free)
Fix it by canceling the delayed work before kfree(dep) in dwc3_gadget_free_endpoints.
Which versions are affected by CVE-2026-89739?
How do I fix CVE-2026-89739?
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-2026-89739 being exploited?
There is no known exploitation of CVE-2026-89739 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-89739, DEBIAN-CVE-2026-89739, GHSA-5q8g-48x9-ppw2, UBUNTU-CVE-2026-89739.