CVE-2020-26268

TensorFlow ImmutableConst type check vulnerability

• CVSS 4.4
• CWE-471 Modification of Assumed-Immutable Data (MAID)
• Memory Corruption
• Local

In affected versions of TensorFlow the tf.raw_ops.ImmutableConst operation returns a constant tensor created from a memory mapped file which is assumed immutable. However, if the type of the tensor is not an integral type, the operation crashes the Python interpreter as it tries to write to the memory area. If the file is too small, TensorFlow properly returns an error as the memory area has fewer bytes than what is needed for the tensor it creates. However, as soon as there are enough bytes, the above snippet causes a segmentation fault. This is because the allocator used to return the buffer data is not marked as returning an opaque handle since the needed virtual method is not overridden. This is fixed in versions 1.15.5, 2.0.4, 2.1.3, 2.2.2, 2.3.2, and 2.4.0.

CVE

CVE-2020-26268

CWE

CWE-471 Modification of Assumed-Immutable Data (MAID)

CVSS base score

4.4

Published

2020-12-10

OWASP

A08 Software and Data Integrity Failures

Orthogonal defect classification

Function

Code defect classification

Incorrect Functionality

Category

Memory Corruption

Subcategory

Buffer Overflows

Accessibility scope

Local

Impact

Denial of Service (DoS)

Affected component

TensorFlow

Fixed by upgrading

Yes

Solution

Update TensorFlow to version 1.15.5, 2.0.4, 2.1.3, 2.2.2, 2.3.2, or 2.4.0.

import tensorflow as tf
import numpy as np
import tempfile

temp_file = tempfile.NamedTemporaryFile(delete=False)
data = np.random.rand(10).astype(np.float32)
data.tofile(temp_file.name)

tensor = tf.raw_ops.ImmutableConst(file=temp_file.name, dtype=tf.float32)
print(tensor)

temp_file.close()

import tensorflow as tf
import numpy as np
import tempfile
import os
import shutil

def create_temp_file(data):
    temp_dir = tempfile.mkdtemp()
    temp_file_path = os.path.join(temp_dir, "temp_data.bin")
    data.tofile(temp_file_path)
    return temp_file_path, temp_dir

try:
    data = np.random.rand(10).astype(np.float32)
    temp_file_path, temp_dir = create_temp_file(data)
    
    tensor = tf.raw_ops.ImmutableConst(file=temp_file_path, dtype=tf.float32)
    print(tensor)
    
finally:
    if os.path.exists(temp_file_path):
        os.remove(temp_file_path)
    if os.path.isdir(temp_dir):
        shutil.rmtree(temp_dir)

@misc{vaitp:cve202026268,
  title        = {{TensorFlow ImmutableConst type check vulnerability}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2020},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2020-26268},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2020-26268/}}
}