Executive brief
A vulnerability in the Linux kernel's Intel graphics driver can cause the entire system to freeze or hang. This occurs when the system attempts to configure Variable Refresh Rate (VRR) display settings in the wrong order, particularly when using certain external monitors or docking stations. An exploit of this flaw would result in a complete loss of system availability, requiring a hard reboot.
Technical details
The vulnerability exists in the drm/i915/vrr component of the Linux kernel. On certain Intel platforms (specifically Ice Lake/ICL), writing to VRR registers such as TRANS_VRR_VMAX or FLIPLINE before the TRANS_DDI_FUNC_CTL register is enabled can trigger a Machine Check Exception (MCE), leading to a kernel hang. This is often triggered during display initialization or link training failures, such as when using faulty cables or specific docking stations. The fix involves reordering the initialization sequence to ensure TRANS_DDI_FUNC_CTL is enabled before VRR timings are configured, aligning the driver behavior with Intel's hardware specifications (BSpec).
Affected products
- Linux Linux Kernel i915 driver versions prior to the fix
Timeline
- 2026-03-03: patched: Initial fix committed to the i915 display driver.
- 2026-05-13: disclosed: CVE-2026-43477 published.