CVE-2020-5215 Segmentation faultin TensorFlow when converting a Python string to tf.float16

Medium 5.0 Published Updated

An attacker can cause a segmentation fault and denial of service in TensorFlow by providing a string where a float16 value is expected during eager execution.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Local or same network only
Victim action needed
A user has to click or open something
Fix
Available

What is CVE-2020-5215?

CVE-2020-5215 is a medium-severity denial of service vulnerability in Google Tensorflow, published on 28 Jan 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official description

In TensorFlow before 1.15.2 and 2.0.1, converting a string (from Python) to a tf.float16 value results in a segmentation fault in eager mode as the format checks for this use case are only in the graph mode. This issue can lead to denial of service in inference/training where a malicious attacker can send a data point which contains a string instead of a tf.float16 value. Similar effects can be obtained by manipulating saved models and checkpoints whereby replacing a scalar tf.float16 value with a scalar string will trigger this issue due to automatic conversions. This can be easily reproduced by tf.constant("hello", tf.float16), if eager execution is enabled. This issue is patched in TensorFlow 1.15.1 and 2.0.1 with this vulnerability patched. TensorFlow 2.1.0 was released after we fixed the issue, thus it is not affected. Users are encouraged to switch to TensorFlow 1.15.1, 2.0.1 or 2.1.0.

Weakness: CWE-20, CWE-754

Which versions are affected by CVE-2020-5215?

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

PackageAffectedFixed in
tensorflow BitnamiAll versions1.15.2, 2.0.1
tensorflow PyPIAll versions1.15.2, 2.0.1
tensorflow PyPIAll versions1.15.2
tensorflow PyPIAll versions1.15.2
tensorflow PyPIFrom 2.0.02.0.1
tensorflow PyPIFrom 2.0.02.0.1
10 more packages
tensorflow-cpu PyPIAll versions1.15.2, 2.0.1
tensorflow-cpu PyPIAll versions1.15.2
tensorflow-cpu PyPIAll versions1.15.2
tensorflow-cpu PyPIFrom 2.0.02.0.1
tensorflow-cpu PyPIFrom 2.0.02.0.1
tensorflow-gpu PyPIAll versions1.15.2, 2.0.1
tensorflow-gpu PyPIAll versions1.15.2
tensorflow-gpu PyPIAll versions1.15.2
tensorflow-gpu PyPIFrom 2.0.02.0.1
tensorflow-gpu PyPIFrom 2.0.02.0.1

Products include Google Tensorflow.

How do I fix CVE-2020-5215?

Upgrade tensorflow to a fixed version for your release line: 1.15.2 or 2.0.1.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2020-5215 being exploited?

There is no known exploitation of CVE-2020-5215 in the wild and no public exploit code.

All Google Tensorflow vulnerabilities

Sources

Also known as BIT-tensorflow-2020-5215, GHSA-977j-xj7q-2jr9, PYSEC-2020-258, PYSEC-2020-303, PYSEC-2020-338.

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