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CVE Record

CVE-2021-37674: Incomplete validation in `MaxPoolGrad` in TensorFlow

TensorFlow is an end-to-end open source platform for machine learning. In affected versions an attacker can trigger a denial of service via a segmentation fault in `tf.raw_ops.MaxPoolGrad` caused by missing validation. The [implementation](https://github.com/tensorflow/tensorflow/blob/460e000de3a83278fb00b61a16d161b1964f15f4/tensorflow/core/kernels/maxpooling_op.cc) misses some validation for the `orig_input` and `orig_output` tensors. The fixes for CVE-2021-29579 were incomplete. We have patched the issue in GitHub commit 136b51f10903e044308cf77117c0ed9871350475. 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.

MediumCVSS 5.5Not KEV-listedUpdated
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This vulnerability can let a low-privileged local user crash TensorFlow by triggering a fault in MaxPoolGrad. The practical business impact is availability loss for affected ML workloads, especially shared compute environments where users can run TensorFlow operations.

Executive priority

Treat this as a moderate availability risk. It is not reported as actively exploited and does not indicate data compromise, but it can disrupt ML workloads where untrusted or semi-trusted users can run TensorFlow code.

Technical view

TensorFlow missed validation for orig_input and orig_output tensors in tf.raw_ops.MaxPoolGrad. Malformed inputs can cause a segmentation fault. This is CWE-20 with CVSS 5.5: local attack vector, low privileges required, no user interaction, and high availability impact only.

Likely exposure

Exposure is most likely in TensorFlow 2.5.0, 2.4.x before 2.4.3, and versions before 2.3.4, especially shared notebooks, batch ML systems, or services that allow users to execute TensorFlow graphs or operations.

Exploitation context

The source bundle does not show CISA KEV listing or cited active exploitation. The advisory describes denial of service, not data theft or code execution. Exploitation requires the ability to run or supply TensorFlow operations in an affected environment.

Researcher notes

This issue is an incomplete fix for CVE-2021-29579. The vulnerable area is MaxPoolGrad input validation in TensorFlow kernel code. The authoritative remediation reference is commit 136b51f10903e044308cf77117c0ed9871350475 and the patched release guidance in TFSA-2021-068/GHSA-7ghq-fvr3-pj2x.

Mitigation direction

  • Upgrade TensorFlow to 2.6.0 or the patched 2.5.1, 2.4.3, or 2.3.4 releases.
  • Apply vendor guidance from the TensorFlow advisory if pinned to affected branches.
  • Restrict untrusted users from executing arbitrary TensorFlow operations on shared ML infrastructure.
  • Prioritize patching shared or multi-tenant ML environments first.

Validation and detection

  • Inventory TensorFlow package versions across notebooks, training images, inference images, and batch workers.
  • Confirm affected deployments are no longer on the vulnerable version ranges listed by TensorFlow.
  • Review ML platforms for untrusted users who can execute TensorFlow ops or submit graphs.
  • Check dependency lockfiles and container base images for pinned TensorFlow versions.
Prepared
Confidence
high
Sources
5

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-20: Exact CWE lookup

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cve · low confidence lookup

CVE-2021-37674 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2021-37674Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
tensorflowtensorflow>= 2.5.0, < 2.5.1, >= 2.4.0, < 2.4.3, < 2.3.4Listed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-20 · source CWE mapping

Improper Input Validation

Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.