Linux Kernel CVE-2026-72090

The amdxdna driver implements DRM (Direct Rendering Manager) infrastructure for AMD's XDNA neural processing unit accelerators, including those embedded in AMD Ryzen AI series SoCs. DRM Buffer Objects (BOs) are reference-counted memory allocations tracked per open DRM file handle - each handle exists within the namespace of the owning drm_file. The vulnerability lies in amdxdna_drm_sync_bo_ioctl(): when handling a SYNC_DIRECT_FROM_DEVICE request, it correctly resolves args->handle against the ioctl caller's file (filp->driver_priv), but then calls amdxdna_hwctx_sync_debug_bo() passing abo->client - the client pointer baked into the buffer object at allocation time - rather than the caller's live file context. Since amdxdna_hwctx_sync_debug_bo() uses that client pointer both as the handle namespace for debug_bo_hdl and to look up hardware contexts in an xarray, a mismatch between the two clients creates a situation where handle resolution and context lookup occur against different security domains. The root cause class, while formally unassigned (CWE: N/A in the advisory), is consistent with CWE-706 (Use of Incorrectly-Resolved Name or Reference) - where object-state context substitutes for ioctl-caller context in a privileged operation.