CVE-2026-63863 drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm()
A kernel bug in the DRM GPU SVM subsystem causes an unbalanced lock release, potentially leading to system instability or 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-2026-63863?
CVE-2026-63863 is a high-severity vulnerability in Linux kernel, published on 19 Jul 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:
drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm()
There is a unbalanced lock/unlock to gpusvm notifier lock: [ 931.045868] ===================================== [ 931.046509] WARNING: bad unlock balance detected! [ 931.047149] 6.19.0-rc6+xe-**************** #9 Tainted: G U [ 931.048150] ------------------------------------- [ 931.048790] kworker/u5:0/51 is trying to release lock (&gpusvm->notifier_lock) at: [ 931.049801] [<ffffffffa090c0d8>] drm_gpusvm_scan_mm+0x188/0x460 [drm_gpusvm_helper] [ 931.050802] but there are no more locks to release! [ 931.051463]
The drm_gpusvm_notifier_unlock() sits under err_free label and the first jump to err_free is just before calling the drm_gpusvm_notifier_lock() causing unbalanced unlock.
Weakness: CWE-667
Which versions are affected by CVE-2026-63863?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-63863?
Apply the vendor's patch.
Is CVE-2026-63863 being exploited?
There is no known exploitation of CVE-2026-63863 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2026-63863, GHSA-6jp3-p375-g5x4, UBUNTU-CVE-2026-63863.