CVE-2026-79611

For XSA-308 logic was introduced, as VMX VMEntry checks do not like the

exact combination of state which occurs when #DB in intercepted, Single

Stepping is active, and blocked by STI/MovSS is active, despite this being

a legitimate state to be in. The resulting VMEntry failure is fatal to

the guest.

Sadly there is another special sub-case of the above, with branch tracing

enabled. In that case the prior adjustment would still cause a VMentry

failure, as before fatal to the guest.