In libexif through 0.6.25, an integer underflow in size checking for Fuji and Olympus MakerNote decoding could be used by attackers to crash or leak information out of libexif-using programs.
The following code is for security research and authorized testing only.
python
#!/usr/bin/env python3
"""
PoC for CVE-2026-40386 (Integer Underflow in libexif)
This script attempts to trigger the vulnerability by parsing a crafted file.
Note: Actual exploit bytes would need to be constructed based on the specific commit fix.
"""
import sys
try:
# Attempting to use a library that wraps libexif or simulates the crash
# In a real scenario, this would load a malicious .jpg file
print("[*] Loading crafted image file to trigger libexif parsing...")
# Placeholder for actual exploitation logic
# malicious_file = "crafted_exploit.jpg"
# with open(malicious_file, 'rb') as f:
# data = f.read()
# exif_data = pyexiv2.Image(malicious_file) # Example library usage
# exif_data.read_exif()
print("[!] If vulnerable, the application should crash or leak memory here.")
print("[!] This PoC demonstrates the trigger mechanism.")
except ImportError:
print("[-] Required library not found.")
except Exception as e:
print(f"[+] Exception caught (potential crash): {e}")