CVE-2020-26271 Heap out of bounds access in MakeEdge in TensorFlow

Medium 4.4 Published 10 Dec 2020 Updated 4 Aug 2024

Loading a malicious saved model in TensorFlow can cause heap out-of-bounds access, potentially leaking memory addresses or causing crashes.

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-2020-26271?

CVE-2020-26271 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 under certain cases, loading a saved model can result in accessing uninitialized memory while building the computation graph. The MakeEdge function creates an edge between one output tensor of the src node (given by output_index) and the input slot of the dst node (given by input_index). This is only possible if the types of the tensors on both sides coincide, so the function begins by obtaining the corresponding DataType values and comparing these for equality. However, there is no check that the indices point to inside of the arrays they index into. Thus, this can result in accessing data out of bounds of the corresponding heap allocated arrays. In most scenarios, this can manifest as unitialized data access, but if the index points far away from the boundaries of the arrays this can be used to leak addresses from the library. 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-908, CWE-125

Which versions are affected by CVE-2020-26271?

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-2020-26271?

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-2020-26271 being exploited?

There is no known exploitation of CVE-2020-26271 in the wild and no public exploit code.

All Google Tensorflow vulnerabilities

Sources

Also known as BIT-tensorflow-2020-26271, GHSA-q263-fvxm-m5mw, PYSEC-2020-257, PYSEC-2020-302, PYSEC-2020-337.