Local privilege escalation via UEFI error handler

Improper input validation in Intel processor UEFI firmware allows local users to escalate privileges through its error handler. Intel identifies the locus as the UEFI firmware error handler but has not disclosed which input it validates incorrectly or how that operation crosses the security boundary. Exploitation requires local access, high privileges, high attack complexity, and additional attack requirements; successful exploitation grants privileges beyond the attacker's initial security context.