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CVE Record

CVE-2021-29587: Division by zero in TFLite's implementation of `SpaceToDepth`

TensorFlow is an end-to-end open source platform for machine learning. The `Prepare` step of the `SpaceToDepth` TFLite operator does not check for 0 before division(https://github.com/tensorflow/tensorflow/blob/5f7975d09eac0f10ed8a17dbb6f5964977725adc/tensorflow/lite/kernels/space_to_depth.cc#L63-L67). An attacker can craft a model such that `params->block_size` would be zero. 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

A crafted TensorFlow Lite model can trigger a division-by-zero crash in the SpaceToDepth operator. The known impact is limited availability loss, not data theft or code execution, and the CVSS score is low. Business urgency rises only where untrusted TFLite models are accepted or processed.

Executive priority

Treat as routine patching unless the organization processes untrusted TFLite models. Prioritize affected model-ingestion services, but this CVE does not indicate confidentiality loss, integrity loss, remote code execution, or known active exploitation in the supplied sources.

Technical view

In TFLite SpaceToDepth, the Prepare step did not check whether params->block_size was zero before division. A crafted model could set block_size to zero and cause a division-by-zero condition. TensorFlow listed fixes for 2.5.0 and supported patched branches 2.4.2, 2.3.3, 2.2.3, and 2.1.4.

Likely exposure

Exposure is most likely in applications, services, or pipelines using affected TensorFlow/TFLite versions and loading TFLite models from users, partners, or other untrusted sources. Systems using only trusted, internally generated models have lower practical exposure.

Exploitation context

The source bundle does not report active exploitation, and KEV status is false. The CVSS vector indicates local attack vector, high attack complexity, low privileges, no user interaction, and low availability impact only.

Researcher notes

Focus validation on TFLite SpaceToDepth model handling and version exposure. Avoid assuming broader TensorFlow runtime impact beyond the affected ranges and operator behavior stated by the advisory. Evidence is sufficient for impact and fixed versions, but incomplete for real-world exploitation status beyond KEV=false.

Mitigation direction

  • Upgrade to TensorFlow 2.5.0 or fixed supported releases 2.4.2, 2.3.3, 2.2.3, or 2.1.4.
  • Inventory services and pipelines that load TensorFlow Lite models.
  • Restrict externally supplied TFLite models until affected deployments are upgraded.
  • Review TensorFlow advisory and fixing commit for exact vendor guidance.

Validation and detection

  • Check deployed TensorFlow and TFLite versions against the affected ranges.
  • Identify workflows accepting TFLite models from users, partners, or automated imports.
  • Confirm upgraded builds include the referenced TensorFlow fix commit.
  • Run existing model ingestion regression tests after upgrade.
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-2021-29587 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-2021-29587Attack 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.