CVE-2026-31756 usb: dwc2: gadget: Fix spin_lock/unlock mismatch in dwc2_hsotg_udc_stop()
A locking mismatch in the Linux kernel's dwc2 USB gadget driver can cause a deadlock, leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-31756?
CVE-2026-31756 is a medium-severity vulnerability in Linux kernel, published on 1 May 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: dwc2: gadget: Fix spin_lock/unlock mismatch in dwc2_hsotg_udc_stop()
dwc2_gadget_exit_clock_gating() internally calls call_gadget() macro, which expects hsotg->lock to be held since it does spin_unlock/spin_lock around the gadget driver callback invocation.
However, dwc2_hsotg_udc_stop() calls dwc2_gadget_exit_clock_gating() without holding the lock. This leads to: - spin_unlock on a lock that is not held (undefined behavior) - The lock remaining held after dwc2_gadget_exit_clock_gating() returns, causing a deadlock when spin_lock_irqsave() is called later in the same function.
Fix this by acquiring hsotg->lock before calling dwc2_gadget_exit_clock_gating() and releasing it afterwards, which satisfies the locking requirement of the call_gadget() macro.
Weakness: CWE-667
Which versions are affected by CVE-2026-31756?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31756?
Apply the vendor's patch.
Is CVE-2026-31756 being exploited?
There is no known exploitation of CVE-2026-31756 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31756, DEBIAN-CVE-2026-31756, GHSA-r5fx-27qq-pwqg, ROOT-OS-UBUNTU-2204-CVE-2026-31756, ROOT-OS-UBUNTU-2404-CVE-2026-31756, UBUNTU-CVE-2026-31756.