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CVE Record

CVE-2021-37662: Reference binding to nullptr in boosted trees in TensorFlow

TensorFlow is an end-to-end open source platform for machine learning. In affected versions an attacker can generate undefined behavior via a reference binding to nullptr in `BoostedTreesCalculateBestGainsPerFeature` and similar attack can occur in `BoostedTreesCalculateBestFeatureSplitV2`. The [implementation](https://github.com/tensorflow/tensorflow/blob/84d053187cb80d975ef2b9684d4b61981bca0c41/tensorflow/core/kernels/boosted_trees/stats_ops.cc) does not validate the input values. We have patched the issue in GitHub commit 9c87c32c710d0b5b53dc6fd3bfde4046e1f7a5ad and in commit 429f009d2b2c09028647dd4bb7b3f6f414bbaad7. The fix will be included in TensorFlow 2.6.0. We will also cherrypick this commit on TensorFlow 2.5.1, TensorFlow 2.4.3, and TensorFlow 2.3.4, as these are also affected and still in supported range.

HighCVSS 7.1Not KEV-listedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-37662 is a TensorFlow bug in boosted-trees calculations. A low-privileged local attacker who can supply crafted inputs to affected operations could trigger undefined behavior, risking data integrity and service availability. It is important for ML platforms using affected TensorFlow versions, but the sources do not show active exploitation.

Executive priority

Patch on the normal high-severity track, faster for shared ML infrastructure or environments processing user-controlled jobs. The business concern is disruption or incorrect computation in affected TensorFlow workloads, not confirmed widespread exploitation.

Technical view

Affected TensorFlow versions do not validate input values in BoostedTreesCalculateBestGainsPerFeature and BoostedTreesCalculateBestFeatureSplitV2, allowing reference binding to nullptr. The issue is CWE-824 with CVSS 3.1 score 7.1, local attack vector, low complexity, low privileges, no user interaction, high integrity and availability impact.

Likely exposure

Exposure is most likely in systems running TensorFlow versions before 2.3.4, 2.4.3, 2.5.1, or 2.6.0 where boosted-trees operations may process inputs controlled by local users, tenants, jobs, or pipelines. Remote-only web exposure is not established by the provided sources.

Exploitation context

The source bundle reports no KEV listing and provides no cited evidence of exploitation in the wild. The CVSS vector indicates local access with low privileges is required, with no user interaction. Treat shared ML notebooks, batch workers, and multi-tenant training infrastructure as higher-risk contexts.

Researcher notes

The public advisory ties the flaw to missing input validation and reference binding to nullptr in boosted-trees stats operations. Analysis should stay focused on affected TensorFlow branches and the two named kernels. The provided sources do not establish remote exploitability, public exploit availability, or exploitation in the wild.

Mitigation direction

  • Upgrade TensorFlow to 2.6.0 or a patched supported release.
  • Use TensorFlow 2.5.1, 2.4.3, or 2.3.4 where branch pinning is required.
  • Restrict untrusted local users or jobs from invoking affected TensorFlow workloads until patched.
  • Check TensorFlow vendor guidance before applying compensating controls.
  • Prioritize patching shared ML and batch-processing environments.

Validation and detection

  • Inventory TensorFlow versions across applications, notebooks, containers, and training images.
  • Flag versions before 2.3.4, 2.4.3, 2.5.1, or 2.6.0.
  • Identify workloads using TensorFlow boosted-trees operations.
  • Confirm patched package versions are deployed in runtime environments.
  • Review whether untrusted users or jobs can submit TensorFlow inputs locally.
Prepared
Confidence
high
Sources
5

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-824: 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.

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cve · low confidence lookup

CVE-2021-37662 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

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
4Source 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
7.1CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H1.85.2Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.1High
CVSS 3.1 vector shape for CVE-2021-37662Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

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>= 2.5.0, < 2.5.1, >= 2.4.0, < 2.4.3, < 2.3.4Listed
Weakness

CWE details

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

CWE-824 · source CWE mapping

Access of Uninitialized Pointer

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