CVE-2026-98765 USB: gadget: dummy-hcd: Fix wait for outstanding request completions

Not scored Published 18 Oct 2026 Updated 21 Oct 2026

A race condition in the Linux kernel dummy-hcd driver allows unloading modules during completion callbacks, potentially leading to code execution or privilege escalation.

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-2026-98765?

CVE-2026-98765 is a 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:

USB: gadget: dummy-hcd: Fix wait for outstanding request completions

The dummy-hcd driver emulates synchronize_irq() by waiting until its private callback_usage counter drops to 0 (with the private lock not held). This counter is incremented whenever a gadget driver callback occurs (which requires the private lock to be dropped), but not when a request completion handler is called.

This is an oversight. Request completion is triggered by timer interrupts (emulating device IRQs in a real UDC), and the interrupt handlers are supposed to have completed when the synchronize_irq() emulation routine returns -- they aren't supposed to be in the middle of a completion callback. If this happens it can lead to a gadget driver's unbind routine running before all outstanding request completions have finished, maybe even allowing the gadget driver's module to be unloaded while a completion handler is still running.

Fix the oversight by incrementing the callback_usage value across request completion callbacks.

Which versions are affected by CVE-2026-98765?

How do I fix CVE-2026-98765?

Apply the vendor's patch.

Is CVE-2026-98765 being exploited?

There is no known exploitation of CVE-2026-98765 in the wild and no public exploit code.

Sources

Also known as AZL-108887, BELL-CVE-2026-98765, DEBIAN-CVE-2026-98765, GHSA-84fc-mwqj-5rjh, UBUNTU-CVE-2026-98765.