cryptidy allows code execution via untrusted data due to pickle.loads

The vulnerability allows an attacker to execute arbitrary code on a system running vulnerable versions of cryptidy. This is achieved by crafting a malicious pickled object and sending it to the aesdecryptmessage function for deserialization. Successful exploitation could lead to complete system compromise, including data theft, modification, or denial of service. The impact is particularly severe because pickle.loads is inherently unsafe when handling untrusted data, as it can execute arbitrary code during deserialization. This resembles other deserialization vulnerabilities that have led to significant breaches.

Systems utilizing cryptidy for symmetric encryption, particularly those processing data from untrusted sources, are at risk. This includes applications that integrate cryptidy for secure communication or data storage, especially if they lack robust input validation mechanisms. Development environments using older versions of cryptidy are also vulnerable.

• python / server:

import os
import pickle

def check_cryptidy_version():
    try:
        import cryptidy
        version = cryptidy.__version__
        if version <= '1.2.4':
            print(f"Vulnerable cryptidy version detected: {version}")
        else:
            print(f"Cryptidy version is safe: {version}")
    except ImportError:
        print("cryptidy is not installed.")

check_cryptidy_version()

1. 2025-10-31Disclosure

   disclosure

1. 予約済み2025-10-27
2. 公開日2025-10-31
3. EPSS 更新日2026-03-23

The primary mitigation for CVE-2025-63675 is to upgrade cryptidy to version 1.2.5 or later, which addresses the insecure use of pickle.loads. If upgrading is not immediately feasible, consider implementing input validation to ensure that only trusted data is passed to the aesdecryptmessage function. While not a complete solution, restricting the source of data used for decryption can reduce the attack surface. Additionally, consider using a safer serialization format like JSON instead of pickle. After upgrading, confirm the fix by attempting to decrypt a known malicious pickled object and verifying that it is rejected or handled safely.