Intel TDX firmware: Improper synchronisation in TDX firmware, exploitable by a privileged host user to escalate

Impact

Improper synchronisation in TDX firmware, exploitable by a privileged host user to escalate. Race conditions in the module are hard to trigger but sit on the tenant boundary.

Who can reach it

Privileged host user, requires winning a race.

What to do

Update the Intel TDX module. The TDX module is loaded by the SEAM loader at boot, so the practical rollout is: stage the new module, drain every trust domain off the node, and reboot. It is not a live-patchable component and running TDs cannot be migrated through it. After the update, every TD must re-attest because the TDX module SVN is part of the attestation report - so anything that pinned the old measurement will fail until you update your attestation policy too. No OEM BIOS release needed for the module itself, which makes this materially faster than a platform firmware update.

References