## https://sploitus.com/exploit?id=51DB045A-E2F9-5E44-BCC1-4E185D2E0ABF
---
## 3. CVE-2026-9999 – Serverless Function Event Injection (Path Traversal → Code Overwrite)
### Overview
A serverless platform that processes object storage events does not sanitize the `object.key` field, allowing an attacker to overwrite the function’s source code via path traversal.
**Severity:** Critical (RCE on next invocation)
### Exploit & Simulation (Python)
```python
#!/usr/bin/env python3
"""
vulnerable_serverless.py - Simulated AWS Lambda-like runtime with event injection.
"""
import json, os, shutil, subprocess
from http.server import HTTPServer, BaseHTTPRequestHandler
FUNCTION_DIR = "/tmp/function"
os.makedirs(FUNCTION_DIR, exist_ok=True)
# initial function code
with open(os.path.join(FUNCTION_DIR, "handler.py"), "w") as f:
f.write("""
def handler(event):
return "Hello, " + event.get('name', 'world')
""")
class Handler(BaseHTTPRequestHandler):
def do_POST(self):
content_length = int(self.headers['Content-Length'])
body = self.rfile.read(content_length)
event = json.loads(body)
# Vulnerable: use event['key'] to decide which file to load?
# Simulate: the function source is overwritten by an "update" event from storage.
if event.get('source') == 'storage':
# Path traversal in object key
object_key = event['object']['key'] # attacker controlled
# Overwrite handler.py with the object content (simulated)
dst = os.path.join(FUNCTION_DIR, "handler.py")
# directory traversal to write outside? But we want to overwrite handler.py.
# Attack: object.key = "../../../tmp/function/handler.py"
# Normalize to ensure it's within FUNCTION_DIR? No validation!
# The "get object" would fetch the file; here we just write injected code.
injected_code = event.get('code', '# no code')
# Resolve the full path – this is the vulnerability:
full_path = os.path.normpath(os.path.join(FUNCTION_DIR, object_key))
# Only check if it is under FUNCTION_DIR? Not present.
with open(full_path, 'w') as f:
f.write(injected_code)
self.send_response(200)
self.end_headers()
self.wfile.write(b"Update applied")
else:
# Execute current handler (for demo)
import handler
result = handler.handler(event)
self.send_response(200)
self.end_headers()
self.wfile.write(result.encode())
server = HTTPServer(('0.0.0.0', 8000), Handler)
server.serve_forever()
```
# CVE-2026-9999 – Serverless Event Injection to Code Overwrite
## đź“– Overview
A path traversal vulnerability in a serverless platform’s event processing allows an attacker to overwrite the function’s source code, leading to remote code execution on subsequent invocations.
## ⚙️ Vulnerability Details
- **Type:** Path Traversal / Insecure File Write
- **Impact:** Remote Code Execution (RCE)
- **Root Cause:** The platform trusts the `object.key` field from storage events without sanitization, allowing `../` sequences to write to arbitrary paths within the function sandbox.
## 🧪 Exploit Demonstration
1. Start the vulnerable runtime:
```bash
python vulnerable_serverless.py