CVE-2026-72313

Received Received - Intake

DRM fb-helper vblank sync fix for active CRTCs

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

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/1c9e0e24-9c4a-4259-8700-cf9e5fd60ca3@suse.de/

CVSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-72313

EUVD

EUVD-2026-59212

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a bug in the Direct Rendering Manager (DRM) framebuffer helper (fb-helper) subsystem. The issue occurs when synchronizing framebuffer output to vertical blank (vblank) signals. The kernel previously attempted to sync to all CRTCs (display controllers), which could cause timeouts and warnings if the framebuffer output was not on the primary CRTC (CRTC 0). The fix ensures only active CRTCs are considered for vblank sync, preventing unnecessary waits and potential deadlocks.

Detection Guidance

This vulnerability is specific to the Linux kernel's DRM subsystem and may manifest as warnings in kernel logs. Check for messages like 'vblank wait timed out on crtc 0' in system logs using commands such as 'dmesg | grep vblank' or 'journalctl -k | grep vblank'.

Impact Analysis

This vulnerability primarily affects systems using the Linux kernel with DRM drivers that support framebuffer output. Users may experience display flickering, timeouts, or system warnings if the framebuffer output is not on the primary display controller. In severe cases, it could lead to temporary display freezes or application crashes during graphics operations.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA. It is a Linux kernel issue related to display synchronization that may cause system warnings but does not involve data exposure or privacy risks.

Mitigation Strategies

Update your Linux kernel to the latest stable version that includes the fix for this issue. Monitor kernel logs for vblank timeout warnings to confirm the issue is resolved after updating.

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