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CVE Record

CVE-2021-29604: Division by zero in TFLite's implementation of hashtable lookup

TensorFlow is an end-to-end open source platform for machine learning. The TFLite implementation of hashtable lookup is vulnerable to a division by zero error(https://github.com/tensorflow/tensorflow/blob/1a8e885b864c818198a5b2c0cbbeca5a1e833bc8/tensorflow/lite/kernels/hashtable_lookup.cc#L114-L115) An attacker can craft a model such that `values`'s first dimension would be 0. The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2, TensorFlow 2.3.3, TensorFlow 2.2.3 and TensorFlow 2.1.4, as these are also affected and still in supported range.

LowCVSS 2.5Not KEV-listedUpdated
Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This is a low-severity denial-of-service issue in TensorFlow Lite. A user who can supply a specially crafted model to an affected TensorFlow installation may trigger a division-by-zero crash in hashtable lookup handling. The sources do not report data theft, data modification, or active exploitation.

Executive priority

Treat as routine maintenance unless the business accepts third-party TFLite models. For exposed model-processing services, schedule prompt upgrade work to reduce crash risk and operational disruption.

Technical view

TensorFlow Lite's hashtable lookup kernel can divide by zero when a crafted model sets the first dimension of `values` to 0. The advisory lists affected TensorFlow release lines before 2.1.4, 2.2.3, 2.3.3, and 2.4.2. Fixes were planned for TensorFlow 2.5.0 and supported backports.

Likely exposure

Exposure is most likely where affected TensorFlow versions load TFLite models supplied by users, partners, customers, or automated pipelines. Systems using only trusted models have lower practical exposure.

Exploitation context

The CVSS vector indicates local access, high attack complexity, low privileges, and low availability impact. CISA KEV status is false, and the provided sources do not claim active exploitation.

Researcher notes

The issue maps to CWE-369 and is limited by the published CVSS vector. The public description identifies the vulnerable TFLite hashtable lookup path and the zero first dimension condition, but no weaponized exploit or active campaign is cited.

Mitigation direction

  • Upgrade to TensorFlow 2.5.0 or the fixed supported backport for your release line.
  • Prioritize systems that accept or process externally supplied TFLite models.
  • Restrict untrusted model uploads and model ingestion paths until upgraded.
  • Review TensorFlow's advisory and commit for vendor-confirmed remediation details.

Validation and detection

  • Inventory TensorFlow versions in applications, containers, notebooks, and ML build images.
  • Identify services that load TFLite models from untrusted or semi-trusted sources.
  • Confirm affected versions are upgraded to a fixed release line.
  • Run existing ML inference regression tests after upgrading TensorFlow.
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-369: Exact CWE lookup

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cve · low confidence lookup

CVE-2021-29604 mapping review

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Vulnerability profileCVE Program record
Severity
Low
CVSS
2.5 (3.1)
Known Exploited
No
Published

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

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
2.5CVSS 3.1LowCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L11.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

2.5Low
CVSS 3.1 vector shape for CVE-2021-29604Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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< 2.1.4, >= 2.2.0, < 2.2.3, >= 2.3.0, < 2.3.3, >= 2.4.0, < 2.4.2Listed
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.