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CVE Record

CVE-2021-29558: Heap buffer overflow in `SparseSplit`

TensorFlow is an end-to-end open source platform for machine learning. An attacker can cause a heap buffer overflow in `tf.raw_ops.SparseSplit`. This is because the implementation(https://github.com/tensorflow/tensorflow/blob/699bff5d961f0abfde8fa3f876e6d241681fbef8/tensorflow/core/util/sparse/sparse_tensor.h#L528-L530) accesses an array element based on a user controlled offset. 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

CVE-2021-29558 is a low-severity TensorFlow flaw where crafted use of SparseSplit can trigger a heap buffer overflow. The documented impact is limited availability loss, not data theft or integrity compromise. It matters mainly where TensorFlow processes untrusted local inputs, models, or workloads on older affected releases.

Executive priority

Handle through normal dependency hygiene unless the organization runs shared or multi-tenant TensorFlow workloads with untrusted inputs. The documented impact is low and availability-focused, but upgrading is straightforward and should be included in routine ML platform maintenance.

Technical view

The vulnerable tf.raw_ops.SparseSplit path accessed an array element using a user-controlled offset, causing a heap buffer overflow. CVSS 3.1 is 2.5 with local attack vector, high complexity, low privileges required, no user interaction, and low availability impact only.

Likely exposure

Exposure is most likely in systems running TensorFlow versions before the fixed releases: 2.1.4, 2.2.3, 2.3.3, 2.4.2, or 2.5.0. Risk is higher when untrusted users, jobs, or ML inputs can reach TensorFlow SparseSplit behavior locally.

Exploitation context

The source bundle does not show active exploitation, and CISA KEV is false. The CVSS vector requires local access and low privileges with high attack complexity. Treat this as a targeted denial-of-service risk in affected ML runtime environments, not a broadly remote compromise issue.

Researcher notes

Evidence supports CWE-787 heap buffer overflow in TensorFlow SparseSplit caused by user-controlled offset indexing. The advisory names fixed releases and affected supported branches. No provided source establishes public exploitation, remote attackability, confidentiality impact, or integrity impact.

Mitigation direction

  • Upgrade TensorFlow to 2.5.0 or a fixed supported branch release.
  • Use TensorFlow 2.4.2, 2.3.3, 2.2.3, or 2.1.4 where branch pinning is required.
  • Check vendor guidance before applying nonstandard backports or downstream package fixes.
  • Limit untrusted local workloads that can execute TensorFlow operations on shared ML infrastructure.

Validation and detection

  • Inventory TensorFlow versions in applications, notebooks, containers, and training images.
  • Confirm dependency lockfiles and runtime images use a fixed TensorFlow release.
  • Review whether untrusted users or jobs can invoke TensorFlow SparseSplit paths.
  • Verify security scanners map TensorFlow packages to CVE-2021-29558 correctly.
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-787: Exact CWE lookup

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Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-29558 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-2021-29558Attack 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-787 · source CWE mapping

Out-of-bounds Write

Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.