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CVE Record

CVE-2021-37691: Division by zero in LSH in TensorFlow Lite

TensorFlow is an end-to-end open source platform for machine learning. In affected versions an attacker can craft a TFLite model that would trigger a division by zero error in LSH [implementation](https://github.com/tensorflow/tensorflow/blob/149562d49faa709ea80df1d99fc41d005b81082a/tensorflow/lite/kernels/lsh_projection.cc#L118). We have patched the issue in GitHub commit 0575b640091680cfb70f4dd93e70658de43b94f9. The fix will be included in TensorFlow 2.6.0. We will also cherrypick thiscommit 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

A specially crafted TensorFlow Lite model can crash affected TensorFlow versions by triggering a divide-by-zero condition. The main business impact is denial of service for systems that process TFLite models, especially where models come from users, partners, or external pipelines.

Executive priority

Treat as a targeted availability risk, not a broad compromise issue. Patch during the normal vulnerability cycle, faster for systems that accept external TFLite models or where service interruption has business impact.

Technical view

CVE-2021-37691 is a CWE-369 divide-by-zero flaw in TensorFlow Lite LSH projection logic. The vendor patched it in commit 0575b640091680cfb70f4dd93e70658de43b94f9, with fixes planned for TensorFlow 2.6.0 and backports to 2.5.1, 2.4.3, and 2.3.4.

Likely exposure

Exposure is most likely where affected TensorFlow versions load TFLite models. Risk rises when model files are user-supplied, partner-provided, downloaded, or otherwise outside direct engineering control.

Exploitation context

The CVSS vector is local, low complexity, low privileges, no user interaction, and high availability impact. The provided sources do not show active exploitation, and the CVE is not listed as KEV in the bundle.

Researcher notes

The strongest evidence is the TensorFlow advisory and fixing commit. The bundle identifies affected TensorFlow ranges and planned fixed releases, but does not provide evidence of exploitation in the wild or broader product-specific impact.

Mitigation direction

  • Upgrade to TensorFlow 2.6.0 or patched supported releases 2.5.1, 2.4.3, or 2.3.4.
  • Inventory applications, services, and mobile or edge builds that load TFLite models.
  • Restrict processing of untrusted TFLite models until affected TensorFlow builds are patched.
  • Check TensorFlow vendor guidance for downstream packaging or additional backport details.

Validation and detection

  • Confirm deployed TensorFlow versions are outside the affected version ranges listed in the CVE bundle.
  • Review model ingestion paths for user-supplied, partner-supplied, or third-party TFLite files.
  • Verify the TensorFlow commit or patched release is present in builds that process TFLite models.
  • Prioritize regression testing for services where model parsing failure can interrupt production workflows.
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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-369: Exact CWE lookup

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cve · low confidence lookup

CVE-2021-37691 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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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-2021-37691Attack 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-369 · source CWE mapping

Divide By Zero

Divide By Zero represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.