CVE-2020-26268 Write to immutable memory region in TensorFlow

Medium 4.4 Published 10 Dec 2020 Updated 4 Aug 2024

An attacker can cause a segmentation fault and crash the Python interpreter by using tf.raw_ops.ImmutableConst with non-integral types on memory-mapped files.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2020-26268?

CVE-2020-26268 is a medium-severity memory corruption vulnerability in Google Tensorflow, published on 10 Dec 2020. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-471

Which versions are affected by CVE-2020-26268?

34 open source packages ship an affected version, including tensorflow, tensorflow-cpu and tensorflow-gpu. It affects 1 product.

Package	Affected	Fixed in
`tensorflow` Bitnami	All versions	`1.15.5, 2.0.4, 2.1.3, 2.2.2, 2.3.2`
`tensorflow` PyPI	All versions	`1.15.5, 2.0.4, 2.1.3, 2.2.2, 2.3.2`
`tensorflow` PyPI	All versions	`1.15.5`
`tensorflow` PyPI	All versions	`1.15.5`
`tensorflow` PyPI	From `2.0.0`	`2.0.4`
`tensorflow` PyPI	From `2.0.0`	`2.0.4`

28 more packages

`tensorflow` PyPI	From `2.1.0`	`2.1.3`
`tensorflow` PyPI	From `2.1.0`	`2.1.3`
`tensorflow` PyPI	From `2.2.0`	`2.2.2`
`tensorflow` PyPI	From `2.2.0`	`2.2.2`
`tensorflow` PyPI	From `2.3.0`	`2.3.2`
`tensorflow` PyPI	From `2.3.0`	`2.3.2`
`tensorflow-cpu` PyPI	All versions	`1.15.5, 2.0.4, 2.1.3, 2.2.2, 2.3.2`
`tensorflow-cpu` PyPI	All versions	`1.15.5`
`tensorflow-cpu` PyPI	All versions	`1.15.5`
`tensorflow-cpu` PyPI	From `2.0.0`	`2.0.4`
`tensorflow-cpu` PyPI	From `2.0.0`	`2.0.4`
`tensorflow-cpu` PyPI	From `2.1.0`	`2.1.3`
`tensorflow-cpu` PyPI	From `2.1.0`	`2.1.3`
`tensorflow-cpu` PyPI	From `2.2.0`	`2.2.2`
`tensorflow-cpu` PyPI	From `2.2.0`	`2.2.2`
`tensorflow-cpu` PyPI	From `2.3.0`	`2.3.2`
`tensorflow-cpu` PyPI	From `2.3.0`	`2.3.2`
`tensorflow-gpu` PyPI	All versions	`1.15.5, 2.0.4, 2.1.3, 2.2.2, 2.3.2`
`tensorflow-gpu` PyPI	All versions	`1.15.5`
`tensorflow-gpu` PyPI	All versions	`1.15.5`
`tensorflow-gpu` PyPI	From `2.0.0`	`2.0.4`
`tensorflow-gpu` PyPI	From `2.0.0`	`2.0.4`
`tensorflow-gpu` PyPI	From `2.1.0`	`2.1.3`
`tensorflow-gpu` PyPI	From `2.1.0`	`2.1.3`
`tensorflow-gpu` PyPI	From `2.2.0`	`2.2.2`
`tensorflow-gpu` PyPI	From `2.2.0`	`2.2.2`
`tensorflow-gpu` PyPI	From `2.3.0`	`2.3.2`
`tensorflow-gpu` PyPI	From `2.3.0`	`2.3.2`

Products include Google Tensorflow.

How do I fix CVE-2020-26268?

Upgrade tensorflow to a fixed version for your release line: 1.15.5, 2.0.4, 2.1.3 or 2.2.2.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2020-26268 being exploited?

There is no known exploitation of CVE-2020-26268 in the wild and no public exploit code.

All Google Tensorflow vulnerabilities

Sources

Also known as BIT-tensorflow-2020-26268, GHSA-hhvc-g5hv-48c6, PYSEC-2020-255, PYSEC-2020-299, PYSEC-2020-334.