Executive brief
A vulnerability in the Linux kernel's AMD display driver could allow a local user to crash the system. The issue occurs when the system attempts to manage display cursors while multiple monitors are connected, leading to a kernel panic. This primarily impacts system availability and could be used to disrupt operations on machines using AMD graphics hardware.
Technical details
A NULL pointer dereference exists in the 'dc_stream_get_scanoutpos' function within the 'amdgpu' driver (drivers/gpu/drm/amd/display/dc/core/dc_stream.c). The vulnerability is triggered during atomic modeset operations involving cursors, specifically when 'stream->ctx' is accessed without a prior NULL check. This was identified using the IGT 'kms_cursor_legacy' test suite on systems with both eDP and DP monitors connected. A local attacker can trigger this condition to cause a kernel Oops, resulting in a denial of service. The fix introduces a mandatory NULL check for 'stream->ctx' before accessing the display context and resource context.
Affected products
- Linux Linux Kernel 4.15 to 6.16.0-99-custom
Timeline
- 2025-11-07: disclosed: Initial patch authored by AMD engineers.
- 2025-12-07: patched: Patch committed to stable kernel trees.
- 2025-12-16: advisory: CVE-2025-68286 published.
References
- https://git.kernel.org/stable/c/09092269cb762378ca8b56024746b1a136761e0d
- https://git.kernel.org/stable/c/109e9c92543f3105e8e1efd2c5e6b92ef55d5743
- https://git.kernel.org/stable/c/3ce62c189693e8ed7b3abe551802bbc67f3ace54
- https://git.kernel.org/stable/c/62150f1e7ec707da76ff353fb7db51fef9cd6557
- https://git.kernel.org/stable/c/781f2f32e9c19eb791b52af283c96f9a9677a7f2
- https://git.kernel.org/stable/c/9d1a65cbe3ec5da3003c8434ac7a38dcdc958fd9
- https://git.kernel.org/stable/c/f7cf491cd5b54b5a093bd3fdf76fa2860a7522bf