Untrusted pointer dereference in Windows DirectX allows an authorized attacker to execute code locally.

Untrusted pointer dereference (CWE-822) in the DirectX Graphics Kernel dxgkrnl.sys host virtual-GPU VMBus provider, Hyper-V guest-to-host remote code execution (Critical, AV:L, PR:L, Scope:Changed, CVSS 8.8). On a Hyper-V host, DXG_HOST_VIRTUALGPU_VMBUS::VmBusQueryAdapterInfo services a guest's D3DKMT QueryAdapterInfo request forwarded over VMBus: it copies the guest's private driver data into a host buffer and passes the request - including the guest-supplied Type - to DxgkQueryAdapterInfoImpl. PRE: the guest-controlled Type reached the implementation unfiltered; for Type == KMTQAITYPE_PHYSICALADAPTERPNPKEY (0x29) the implementation dereferences a pointer derived from the request data - an untrusted pointer dereference executed in the host kernel on behalf of the guest. Because a low-privileged guest actor can drive this against the host (Scope changes from guest to host), it is a guest-to-host RCE primitive (Critical 8.8). Diff of dxgkrnl.sys 10.0.26100.8737 -> .8875 (Jul 14 2026, KB5101650, 24H2/Server 2025) confirms the fix: gated behind CFR flag Feature_2095820091, VmBusQueryAdapterInfo (ratio 0.63) now rejects Type == 0x29 over VMBus - it logs a triage event (DxgkLogTriageEvent 'Unsupported QueryAdapterInfo type over VMBus: 0x%I64x') and returns STATUS_INVALID_PARAMETER instead of calling DxgkQueryAdapterInfoImpl. Confirmation level: the fix rejects the query type at the VMBus boundary; the exact pointer dereference inside DxgkQueryAdapterInfoImpl was not traced, so no specific memory-corruption primitive is asserted. Cross-checked against an independent writeup (function, string, and 0x29 constant match the ghidriff; the writeup cites Feature_2364255544 while the ghidriff shows Feature_2095820091).

A guest VM's QueryAdapterInfo(PHYSICALADAPTERPNPKEY) over VMBus drives an untrusted pointer dereference in the host kernel

Derived from the patch delta: the checks added by the vendor identify which fields crossed a trust boundary unvalidated. Reachability and privilege are taken from the call chain in the RCA report.

pwn2addr