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CVE Record

CVE-2021-29519: CHECK-fail in SparseCross due to type confusion

TensorFlow is an end-to-end open source platform for machine learning. The API of `tf.raw_ops.SparseCross` allows combinations which would result in a `CHECK`-failure and denial of service. This is because the implementation(https://github.com/tensorflow/tensorflow/blob/3d782b7d47b1bf2ed32bd4a246d6d6cadc4c903d/tensorflow/core/kernels/sparse_cross_op.cc#L114-L116) is tricked to consider a tensor of type `tstring` which in fact contains integral elements. Fixing the type confusion by preventing mixing `DT_STRING` and `DT_INT64` types solves this issue. 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 TensorFlow SparseCross bug can let a low-privileged local user or local code path crash a process by triggering a type-confusion CHECK failure. The disclosed impact is limited availability loss, not data theft or code execution. Business urgency is low unless vulnerable TensorFlow is exposed in production pipelines that process untrusted inputs.

Executive priority

Treat as a low-priority reliability fix unless TensorFlow workloads are multi-tenant or process untrusted local inputs. Patch through normal dependency maintenance, with faster action for shared ML platforms where one user can disrupt jobs for others.

Technical view

tf.raw_ops.SparseCross allowed invalid DT_STRING and DT_INT64 type mixing, causing the kernel to mis-handle tensor contents and fail a CHECK. The issue is CWE-843 with CVSS 3.1 score 2.5. Fixed releases were planned for TensorFlow 2.5.0 and cherrypicked to 2.4.2, 2.3.3, 2.2.3, and 2.1.4.

Likely exposure

Exposure is limited to systems running affected TensorFlow versions and invoking tf.raw_ops.SparseCross, especially where local users, jobs, notebooks, or pipelines can influence tensor inputs. The source bundle does not indicate remote unauthenticated exposure.

Exploitation context

The CVSS vector indicates local access, high attack complexity, low privileges required, no user interaction, and low availability impact only. KEV is false, and the provided sources do not report active exploitation.

Researcher notes

The root issue is type confusion in TensorFlow SparseCross. The advisory states preventing DT_STRING and DT_INT64 mixing resolves it. Evidence supports denial of service only; there is no cited confidentiality, integrity, remote exploitation, or active exploitation evidence.

Mitigation direction

  • Upgrade TensorFlow to 2.5.0 or an applicable fixed cherrypick release.
  • Prioritize 2.4.2, 2.3.3, 2.2.3, or 2.1.4 for supported affected branches.
  • Review vendor advisory before relying on unsupported TensorFlow versions.
  • Restrict who can run untrusted TensorFlow jobs in shared environments.
  • Monitor ML job failures for repeated SparseCross-related crashes.

Validation and detection

  • Inventory TensorFlow versions across production, CI, notebooks, and model-serving images.
  • Check dependency manifests and runtime environments for affected version ranges.
  • Identify code paths that invoke tf.raw_ops.SparseCross or SparseCross wrappers.
  • Confirm deployed images use a fixed TensorFlow release.
  • Review crash logs for TensorFlow CHECK failures involving SparseCross.
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-843: Exact CWE lookup

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cve · low confidence lookup

CVE-2021-29519 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-2021-29519Attack 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-843 · source CWE mapping

Access of Resource Using Incompatible Type ('Type Confusion')

Access of Resource Using Incompatible Type ('Type Confusion') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.