How severe is CVE-2021-41207?

CVE-2021-41207 has a CVSS score of 5.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-41207?

CVE-2021-41207 affects the following packages: tensorflow (PyPI), tensorflow (PyPI), tensorflow (PyPI), tensorflow-cpu (PyPI), tensorflow-cpu (PyPI), tensorflow-cpu (PyPI), tensorflow-gpu (PyPI), tensorflow-gpu (PyPI), and 1 more. Ecosystems affected: PyPI.

How do I fix CVE-2021-41207?

Update tensorflow to 2.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41207 is resolved across your whole dependency graph.

How do I detect CVE-2021-41207 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tensorflow, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-41207 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2021-41207 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-41207 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-41207?

CVE-2021-41207 has an EPSS (Exploit Prediction Scoring System) score of 0.1%, placing it in the 3th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-41207?

CVE-2021-41207 is classified as CWE-369 (CWE-369). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-41207 published, and has it been updated?

CVE-2021-41207 was published on November 5, 2021 and was last updated on August 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

MEDIUM severity

CVE-2021-41207 — tensorflow

MEDIUMFix: tensorflow/tensorflow@f2c3931

CVE-2021-41207 is a medium-severity (CVSS 5.5) CWE-369 vulnerability in tensorflow. A fix is available for tensorflow — see the affected versions and patch details below.

FPE in `ParallelConcat`

Also known asBIT-tensorflow-2021-41207GHSA-7v94-64hj-m82hPYSEC-2021-399PYSEC-2021-616PYSEC-2021-814

Published

Nov 5, 2021

Updated

Aug 7, 2026

Affected

9 pkgs

Patched

9 / 9

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs3th percentile — riskier than 3% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-41207 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

9 pkgs affected

🐍tensorflow🐍tensorflow🐍tensorflow🐍tensorflow-cpu🐍tensorflow-cpu🐍tensorflow-cpu🐍tensorflow-gpu🐍tensorflow-gpu+1 more

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The implementation of ParallelConcat misses some input validation and can produce a division by 0:

import tensorflow as tf

@tf.function
def test():
  y = tf.raw_ops.ParallelConcat(values=[['tf']],shape=0)
  return y

test()

Patches

We have patched the issue in GitHub commit f2c3931113eaafe9ef558faaddd48e00a6606235.

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.

For more information

Please consult our security guide for more information regarding the security model and how to contact us with issues and questions.

Attribution

This vulnerability has been reported by members of the Aivul Team from Qihoo 360.

Affected Packages

9 total 9 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`tensorflow`	≥ 2.6.0&&< 2.6.1	2.6.1`pip install --upgrade 'tensorflow==2.6.1'`
🐍PyPI	`tensorflow`	≥ 2.5.0&&< 2.5.2	2.5.2`pip install --upgrade 'tensorflow==2.5.2'`
🐍PyPI	`tensorflow`	all versions	2.4.4`pip install --upgrade 'tensorflow==2.4.4'`
🐍PyPI	`tensorflow-cpu`	all versions	2.4.4`pip install --upgrade 'tensorflow-cpu==2.4.4'`
🐍PyPI	`tensorflow-cpu`	≥ 2.5.0&&< 2.5.2	2.5.2`pip install --upgrade 'tensorflow-cpu==2.5.2'`
🐍PyPI	`tensorflow-cpu`	≥ 2.6.0&&< 2.6.1	2.6.1`pip install --upgrade 'tensorflow-cpu==2.6.1'`

Affected Products

1 product · 5 configurations

Application

tensorflowgoogle

≥ 2.6.0 && < 2.6.1

1 version

2.7.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tensorflow, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update tensorflow to 2.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41207 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact The [implementation of `ParallelConcat`](https://github.com/tensorflow/tensorflow/blob/8d72537c6abf5a44103b57b9c2e22c14f5f49698/tensorflow/core/kernels/inplace_ops.cc#L72-L97) misses some input validation and can produce a division by 0: ```python import tensorflow as tf @tf.function def test(): y = tf.raw_ops.ParallelConcat(values=[['tf']],shape=0) return y test() ``` ### Patches We have patched the issue in GitHub commit [f2c3931113eaafe9ef558faaddd48e00a6606235](https://github.com/tensorflow/tensorflow/commit/f2c3931113eaafe9ef558faaddd48e00a6606235). The fix will be inc

O3 Security · Impact-Aware SCA

Is CVE-2021-41207 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

5.5/10CVSS v3 base

Vector breakdown

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Raw vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE Classification

CWE-369CWE-369

Weaponization

No known public exploit tooling found.

OpenSSF Scorecard

Package health score

tensorflow

7.6/10

Maintained10/10

Code-Review4/10

Dependency-Update-Tool10/10

Branch-ProtectionN/A

Vulnerabilities0/10

Assessed Oct 10, 2026

Timeline

Disclosed

Nov 5, 2021

Last updated

Aug 7, 2026

Identifiers

CVE-2021-41207

GHSA-7v94-64hj-m82h

BIT-tensorflow-2021-41207

PYSEC-2021-399

PYSEC-2021-616

References

Advisorygithub.com Advisorynvd.nist.gov Fixgithub.com Webgithub.com Webgithub.com Webgithub.com Webgithub.com Webgithub.com Webgithub.com Webgithub.com Packagegithub.com

Related vulnerabilities

This CVE is medium severity; 8 of 8 other CVEs affecting tensorflow are rated as high or higher (top: high).

CVE-2023-33976CVE-2023-25661CVE-2023-25670CVE-2023-25665CVE-2023-27579CVE-2023-25673CVE-2023-25663CVE-2023-25658

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedAug 7, 2026

CVE-2021-41207 — tensorflow

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Impact

Patches

For more information

Attribution

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2021-41207 in your dependencies?