Executive brief
The AMD GPU compute driver (KFD) in the Linux kernel failed to properly authorize debug session termination requests. A user with access to /dev/kfd could forcibly terminate another process's active GPU debug session without proper permissions, potentially disrupting development workflows and allowing interference with other users' debugging activities.
Technical details
An authorization bypass vulnerability exists in the kfd_ioctl_set_debug_trap function within drivers/gpu/drm/amd/amdkfd/kfd_chardev.c. The vulnerability stems from an incomplete permission check that previously excluded the KFD_IOC_DBG_TRAP_DISABLE operation from ptrace authorization verification. Any user with file descriptor access to /dev/kfd could invoke KFD_IOC_DBG_TRAP_DISABLE to terminate another process's GPU debug session without ownership or active ptrace relationship. The fix adds consistent authorization checks across all debug trap operations, requiring either same-process context or valid ptrace relationship (including debugger_process field verification) for cross-process debug operations. The vulnerability is local, requires /dev/kfd access, and is fixed in kernel commits 4db4c5ffd5585b72622ecf6ffedf2da258ee23f5 (upstream) and backported variants.
Affected products
- Linux Linux kernel Affects multiple stable branches; patched in commits 4db4c5ffd5585b72622ecf6ffedf2da258ee23f5 and 99b2fe4f19e3be0a8d0a0b5ea98d855970889653
Timeline
- 2026-07-14: disclosed: Commit authored by Gang Ba
- 2026-07-28: patched: Upstream fix merged
- 2026-08-09: other: Cherry-picked to stable branches
- 2026-08-28: advisory: CVE-2026-80703 published