CVE-2026-72313 drm/fb-helper: Only consider active CRTCs for vblank sync
A flaw in the Linux kernel DRM fb-helper allows local attackers to cause a denial of service via vblank synchronization timeouts on inactive CRTCs.
- 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-2026-72313?
CVE-2026-72313 is a denial of service vulnerability in Linux, published on 15 Aug 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/fb-helper: Only consider active CRTCs for vblank sync
Only synchronize fbdev output to the vblank of an active CRTC. Go over the list of CRTCs and pick the first that matches. Fixes warnings as the one shown below
[ 77.201354] WARNING: drivers/gpu/drm/drm_vblank.c:1320 at drm_crtc_wait_one_vblank+0x194/0x1cc [drm], CPU#1: kworker/1:7/1867 [ 77.201354] omapdrm omapdrm.0: [drm] vblank wait timed out on crtc 0
This currently happens if the fbdev output is not on CRTC 0.
Atomic and non-atomic drivers require distinct code paths. As for other fbdev operations, implement both and select the correct one at runtime.
Not finding an active CRTC is not a bug. Do not wait in this case, but flush the display update as before.
v4: - avoid possible deadlocks with locking context (Sashiko) v3: - drop excessive state validation (Jani) - acquire plane and CRTC mutices (Sashiko) v2: - move look-up code into separate helper - support drivers with legacy modesetting v1: - see https://lore.kernel.org/dri-devel/[email protected]/
Which versions are affected by CVE-2026-72313?
How do I fix CVE-2026-72313?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-72313 being exploited?
There is no known exploitation of CVE-2026-72313 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-72313, GHSA-c7fw-jq78-v3p5, UBUNTU-CVE-2026-72313.