What is CVE-2021-37678?

CVE-2021-37678 is a critical-severity vulnerability in Google Tensorflow, classified under Deserialization of Untrusted Data. CVSS score: 9.3/10. Published 2021-08-12.

How severe is CVE-2021-37678?

Critical severity. CVSS v3 base score is 9.3 out of 10.

Is CVE-2021-37678 known to be exploited?

5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Deserialization in Google Tensorflow

CVE-2021-37678

TensorFlow is an end-to-end open source platform for machine learning. In affected versions TensorFlow and Keras can be tricked to perform arbitrary code execution when deserializing a Keras model from YAML format. The [implementation](https://github.com/tensorflow/tensorflow/blob/460e000de3a83278fb00b61a16d161b1964f15f4/tensorflow/python/keras/saving/model_config.py#L66-L104) uses `yaml.unsafe_load` which can perform arbitrary code execution on the input. Given that YAML format support requires a significant amount of work, we have removed it for now. We have patched the issue in GitHub commit 23d6383eb6c14084a8fc3bdf164043b974818012. The fix will be included in TensorFlow 2.6.0. We will also cherrypick this commit on TensorFlow 2.5.1, TensorFlow 2.4.3, and TensorFlow 2.3.4, as these are also affected and still in supported range.

Vulnerability class: Insecure Deserialization

Published 2021-08-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (36.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Google Tensorflow — versions 2.5.0, 2.6.0
Tensorflow — versions >= 2.5.0, < 2.5.1, >= 2.4.0, < 2.4.3, < 2.3.4

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

Public proof-of-concept exploits

References

github.com/tensorflow/tensorflow/security/advisories/GHSA-r6jx-9g48-2r5r (Third Party Advisory)
github.com/tensorflow/tensorflow/commit/23d6383eb6c14084a8fc3bdf164043b974818012 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-37678?: CVE-2021-37678 is a critical-severity vulnerability in Google Tensorflow, classified under Deserialization of Untrusted Data. CVSS score: 9.3/10. Published 2021-08-12.
How severe is CVE-2021-37678?: Critical severity. CVSS v3 base score is 9.3 out of 10.
Is CVE-2021-37678 known to be exploited?: 5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.