Executive brief
AMD KFD's CRIU checkpoint feature in the Linux kernel contains a memory safety flaw that allows kernel data to leak to user processes. When checkpointing GPU compute queues, the code reads beyond the allocated control stack buffer into adjacent kernel memory without bounds checking, potentially exposing sensitive kernel information to unprivileged user applications.
Technical details
The vulnerability is a buffer over-read (out-of-bounds read) in the drm/amdkfd driver's CRIU (Checkpoint/Restore In Userspace) checkpoint mechanism. The checkpoint_mqd() and related functions use the hardware field cp_hqd_cntl_stack_size without validating it against the allocated BO (buffer object) size, allowing memcpy to read past the BO boundary into adjacent GTT (Graphics Translation Table) memory. The fix clamps the copy size to min(hardware_field, allocated_size) and stores the control stack BO size in the mqd_manager structure. No authentication or special privileges are required beyond existing GPU compute queue access. The patch was merged upstream in June 2026 (commit 426ffae6) and backported to stable kernels.
Affected products
- Linux Linux Kernel v5.1 through v6.9 and stable branches (patched in v6.10.y, v6.9.y, and other stable series)
Timeline
- 2026-08-12: disclosed: Published in NVD
- 2026-06-02: patched: Upstream commit 426ffae6ecc7ec77d32bf8be065c21a1b881b084
- 2026-08-03: patched: Backported to stable kernels (e.g., commit a0d87beb in stable tree)