CME-105

SMEP (Supervisor Mode Execution Prevention)

Harden OS/Kernel High Confidence

Description

CPU feature preventing the kernel from executing code in userspace pages. Blocks ret2usr attacks where kernel exploit redirects execution to attacker-controlled userspace code.

CVSS Vector Impacts

Metric	Transition	Rationale
Attack Complexity (AC)	L → H	Kernel exploit cannot simply jump to userspace shellcode
Scope (S)	C → U	Prevents trivial kernel-to-userspace execution boundary crossing

CWE Relationships

CWE-119 CWE-269

Verification

Check CPU flags for smep support

$ grep -o smep /proc/cpuinfo | head -1
# Expected: smep

Platform: linux