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CVE Record

CVE-2021-37677: Missing validation in shape inference for `Dequantize` in TensorFlow

TensorFlow is an end-to-end open source platform for machine learning. In affected versions the shape inference code for `tf.raw_ops.Dequantize` has a vulnerability that could trigger a denial of service via a segfault if an attacker provides invalid arguments. The shape inference [implementation](https://github.com/tensorflow/tensorflow/blob/460e000de3a83278fb00b61a16d161b1964f15f4/tensorflow/core/ops/array_ops.cc#L2999-L3014) uses `axis` to select between two different values for `minmax_rank` which is then used to retrieve tensor dimensions. However, code assumes that `axis` can be either `-1` or a value greater than `-1`, with no validation for the other values. We have patched the issue in GitHub commit da857cfa0fde8f79ad0afdbc94e88b5d4bbec764. 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

CVE-2021-37677 is a TensorFlow denial-of-service flaw. Invalid arguments to Dequantize shape inference can crash the process with a segmentation fault. It does not indicate data theft or code execution, but it can disrupt ML workloads that process attacker-controlled inputs.

Executive priority

Treat as a moderate reliability risk. Patch on normal security maintenance timelines, sooner for shared ML platforms or services that process untrusted ML inputs where a crash could affect customers or operations.

Technical view

TensorFlow’s shape inference for tf.raw_ops.Dequantize failed to validate axis before using it to determine minmax_rank and access tensor dimensions. Unexpected axis values could trigger a segfault. The issue is CWE-20 with CVSS 3.1 score 5.5 and availability impact only.

Likely exposure

Exposure is mainly affected TensorFlow deployments using vulnerable versions where a local low-privileged actor, or an application path reachable by such input, can supply invalid Dequantize arguments. Listed affected ranges include TensorFlow before 2.3.4, 2.4.x before 2.4.3, and 2.5.x before 2.5.1.

Exploitation context

The CVSS vector is local, low complexity, low privilege, no user interaction, with high availability impact. The source bundle does not show CISA KEV listing or other evidence of active exploitation.

Researcher notes

The root cause is missing validation of axis in TensorFlow array_ops.cc shape inference for Dequantize. The advisory states the fix is commit da857cfa0fde8f79ad0afdbc94e88b5d4bbec764 and is included or cherry-picked into named fixed releases.

Mitigation direction

  • Upgrade TensorFlow to 2.6.0 or a supported fixed maintenance release.
  • Use TensorFlow 2.5.1, 2.4.3, or 2.3.4 where applicable.
  • Check TensorFlow’s advisory for any branch-specific guidance.
  • Restrict untrusted model or operation inputs until upgraded.
  • Prioritize systems where crashes affect production ML services.

Validation and detection

  • Inventory TensorFlow versions across production, CI, notebooks, and containers.
  • Confirm affected ranges are not present in deployed environments.
  • Review ML services that accept externally supplied models or operation parameters.
  • Verify runtime dependency lockfiles resolve to fixed TensorFlow releases.
  • Document whether Dequantize-related inputs can cross trust boundaries.
Prepared
Confidence
high
Sources
4

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-2021-37677 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
3Source 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-2021-37677Attack 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.