LiveActive security incident?Get immediate response
CVE Record

CVE-2021-29565: Null pointer dereference in `SparseFillEmptyRows`

TensorFlow is an end-to-end open source platform for machine learning. An attacker can trigger a null pointer dereference in the implementation of `tf.raw_ops.SparseFillEmptyRows`. This is because of missing validation(https://github.com/tensorflow/tensorflow/blob/fdc82089d206e281c628a93771336bf87863d5e8/tensorflow/core/kernels/sparse_fill_empty_rows_op.cc#L230-L231) that was covered under a `TODO`. If the `dense_shape` tensor is empty, then `dense_shape_t.vec<>()` would cause a null pointer dereference in the implementation of the op. 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
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This is a low-severity TensorFlow denial-of-service issue. A local, low-privileged user who can run or influence TensorFlow operations could trigger a crash in SparseFillEmptyRows by supplying an empty dense_shape tensor. It does not expose data or allow code execution based on the provided sources.

Executive priority

Treat as routine patching unless TensorFlow is exposed in multi-user ML platforms. The business risk is service disruption, not compromise. Prioritize shared compute, hosted notebooks, and customer-controlled ML workloads first.

Technical view

CVE-2021-29565 is a CWE-476 null pointer dereference in tf.raw_ops.SparseFillEmptyRows. Missing validation allowed dense_shape_t.vec<>() to dereference null when dense_shape was empty. CVSS 3.1 is 2.5: local attack vector, high complexity, low privileges, no confidentiality or integrity impact, and low availability impact.

Likely exposure

Exposure is most likely in systems using affected TensorFlow versions before 2.1.4, 2.2.3, 2.3.3, or 2.4.2, especially where users or jobs can submit model code or tensors to shared ML infrastructure.

Exploitation context

The provided sources do not report active exploitation, and the CVE is not in KEV. Exploitation requires local access, low privileges, and high complexity. The known impact is process availability disruption, not data theft or privilege escalation.

Researcher notes

The key condition is an empty dense_shape tensor reaching SparseFillEmptyRows. The fix is linked to TensorFlow commit faa76f39014ed3b5e2c158593b1335522e573c7f. Evidence supports low availability impact only; no source indicates remote exploitation or broader compromise.

Mitigation direction

  • Upgrade TensorFlow to 2.5.0 or a patched supported branch release.
  • For older branches, use 2.4.2, 2.3.3, 2.2.3, or 2.1.4 as applicable.
  • Check TensorFlow vendor advisory before relying on unsupported versions.
  • Restrict untrusted users from submitting arbitrary TensorFlow operations to shared runtimes.

Validation and detection

  • Inventory TensorFlow versions in application, notebook, training, and serving environments.
  • Flag versions matching the affected ranges listed in the CVE source bundle.
  • Review code paths using tf.raw_ops.SparseFillEmptyRows or accepting sparse tensor input.
  • Confirm patched versions are deployed in production and batch ML images.
Prepared
Confidence
high
Sources
4

Public sources used

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-476: 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-2021-29565 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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-2021-29565Attack 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

Source materials

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-476

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-476 · source CWE mapping

NULL Pointer Dereference

NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs