Intel 4th Gen Xeon on-chip debug and test interface (with SGX or TDX): MULTI-TENANT ISOLATION: The on-chip debug

Impact

MULTI-TENANT ISOLATION: The on-chip debug and test interface has improper access control on 4th-generation Xeon when SGX or TDX is enabled, giving a privileged user escalation. Debug interfaces reaching into a TEE is the single worst shape for a confidential-compute claim, because it bypasses the architectural boundary entirely rather than working around it.

Who can reach it

Privileged local access on the host.

What to do

Microcode/platform firmware update plus TCB recovery. Where the fix lands in microcode it can be late-loaded at boot; where it lands in BIOS, expect the OEM lag. Re-attest afterwards.

References