CVE-2021-41213 Deadlock in mutually recursive `tf.function` objects

Medium 5.5 Published Updated

An attacker can cause a denial of service by forcing the loading of models with mutually recursive functions, leading to a deadlock in TensorFlow.

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-2021-41213?

CVE-2021-41213 is a medium-severity denial of service vulnerability in Google Tensorflow, published on 5 Nov 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

TensorFlow is an open source platform for machine learning. In affected versions the code behind `tf.function` API can be made to deadlock when two `tf.function` decorated Python functions are mutually recursive. This occurs due to using a non-reentrant `Lock` Python object. Loading any model which contains mutually recursive functions is vulnerable. An attacker can cause denial of service by causing users to load such models and calling a recursive `tf.function`, although this is not a frequent scenario. The fix will be included in TensorFlow 2.7.0. We will also cherrypick this commit on TensorFlow 2.6.1, TensorFlow 2.5.2, and TensorFlow 2.4.4, as these are also affected and still in supported range.

Weakness: CWE-662, CWE-667

Which versions are affected by CVE-2021-41213?

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

PackageAffectedFixed in
tensorflow BitnamiFrom 2.4.02.4.4, 2.5.2, 2.6.1
tensorflow PyPIAll versions2.4.4, 2.5.2, 2.6.1, 2.7.0
tensorflow PyPIAll versions2.4.4
tensorflow PyPIAll versions2.4.4
tensorflow PyPIFrom 2.5.02.5.2
tensorflow PyPIFrom 2.5.02.5.2
16 more packages
tensorflow PyPIFrom 2.6.02.6.1
tensorflow PyPIFrom 2.6.02.6.1
tensorflow-cpu PyPIAll versions2.4.4, 2.5.2, 2.6.1, 2.7.0
tensorflow-cpu PyPIAll versions2.4.4
tensorflow-cpu PyPIAll versions2.4.4
tensorflow-cpu PyPIFrom 2.5.02.5.2
tensorflow-cpu PyPIFrom 2.5.02.5.2
tensorflow-cpu PyPIFrom 2.6.02.6.1
tensorflow-cpu PyPIFrom 2.6.02.6.1
tensorflow-gpu PyPIAll versions2.4.4, 2.5.2, 2.6.1, 2.7.0
tensorflow-gpu PyPIAll versions2.4.4
tensorflow-gpu PyPIAll versions2.4.4
tensorflow-gpu PyPIFrom 2.5.02.5.2
tensorflow-gpu PyPIFrom 2.5.02.5.2
tensorflow-gpu PyPIFrom 2.6.02.6.1
tensorflow-gpu PyPIFrom 2.6.02.6.1

Products include Google Tensorflow.

How do I fix CVE-2021-41213?

Upgrade tensorflow to a fixed version for your release line: 2.4.4, 2.5.2, 2.6.1 or 2.7.0.

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-2021-41213 being exploited?

There is no known exploitation of CVE-2021-41213 in the wild and no public exploit code.

All Google Tensorflow vulnerabilities

Sources

Also known as BIT-tensorflow-2021-41213, GHSA-h67m-xg8f-fxcf, PYSEC-2021-405, PYSEC-2021-622, PYSEC-2021-820.

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