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CVE Record

CVE-2021-29522: Division by 0 in `Conv3DBackprop*`

TensorFlow is an end-to-end open source platform for machine learning. The `tf.raw_ops.Conv3DBackprop*` operations fail to validate that the input tensors are not empty. In turn, this would result in a division by 0. This is because the implementation(https://github.com/tensorflow/tensorflow/blob/a91bb59769f19146d5a0c20060244378e878f140/tensorflow/core/kernels/conv_grad_ops_3d.cc#L430-L450) does not check that the divisor used in computing the shard size is not zero. Thus, if attacker controls the input sizes, they can trigger a denial of service via a division by zero error. 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 TensorFlow flaw can crash a process when specific 3D convolution backpropagation operations receive empty tensors. The business impact is denial of service, not data theft or code execution. Risk is mainly for ML systems where users or tenants can influence tensor shapes or model execution paths on affected TensorFlow versions.

Executive priority

Treat this as a low-priority availability fix unless affected TensorFlow workloads are multi-tenant or exposed to untrusted model inputs. Patch during normal maintenance, but address shared ML platforms sooner because a crash could disrupt other users.

Technical view

`tf.raw_ops.Conv3DBackprop*` did not validate non-empty input tensors before calculating shard size. A zero divisor could cause a division-by-zero crash. Sources rate it low severity with CVSS 2.5, local attack vector, high complexity, low privileges, and low availability impact only.

Likely exposure

Exposure is most plausible in training, research, notebook, or ML-serving environments running affected TensorFlow versions and accepting user-controlled tensor sizes, models, or computation graphs. Systems that do not expose TensorFlow execution to untrusted users are less likely to be affected.

Exploitation context

The source bundle does not show KEV listing or active exploitation. The advisory states an attacker who controls input sizes can trigger denial of service. Evidence supports crash-oriented abuse only, not privilege escalation, data compromise, or remote code execution.

Researcher notes

The bug is narrowly scoped to TensorFlow `Conv3DBackprop*` operations and empty tensor handling. Available sources identify CWE-369 and a division-by-zero denial of service. No source in the bundle supports broader impact or active exploitation claims.

Mitigation direction

  • Upgrade TensorFlow to 2.5.0 or a listed patched maintenance release.
  • Use TensorFlow 2.4.2, 2.3.3, 2.2.3, or 2.1.4 where applicable.
  • Restrict untrusted control over tensor shapes, models, and raw operation execution.
  • Apply vendor guidance for unsupported or pinned TensorFlow deployments.
  • Prioritize shared ML platforms where one user can affect others.

Validation and detection

  • Inventory TensorFlow versions in applications, notebooks, containers, and training images.
  • Check dependency lockfiles and runtime package versions for affected ranges.
  • Identify endpoints or jobs accepting user-controlled tensor dimensions or uploaded models.
  • Confirm patched TensorFlow versions are deployed in production and CI images.
  • Review monitoring for repeated TensorFlow worker crashes or availability errors.
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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-369: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-29522 mapping review

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Open ATT&CK lookup
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-2021-29522Attack 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.