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CVE Record

CVE-2021-29551: OOB read in `MatrixTriangularSolve`

TensorFlow is an end-to-end open source platform for machine learning. The implementation of `MatrixTriangularSolve`(https://github.com/tensorflow/tensorflow/blob/8cae746d8449c7dda5298327353d68613f16e798/tensorflow/core/kernels/linalg/matrix_triangular_solve_op_impl.h#L160-L240) fails to terminate kernel execution if one validation condition fails. 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 is a low-severity TensorFlow bug in a matrix-solving operation. A failed validation check could let kernel execution continue and read beyond expected memory. The published impact is limited availability loss, not data theft or tampering. Exposure matters mainly where users can run TensorFlow workloads or submit models/tensors to a service.

Executive priority

Low priority unless TensorFlow is used in multi-tenant or user-submitted ML workloads. Schedule patching through normal dependency maintenance, but do not defer indefinitely on shared compute platforms.

Technical view

CVE-2021-29551 is a CWE-125 out-of-bounds read in TensorFlow MatrixTriangularSolve. The implementation did not terminate execution after one validation failure. CVSS 3.1 is 2.5 with local access, high attack complexity, low privileges, no user interaction, and low availability impact only.

Likely exposure

Systems using TensorFlow versions before 2.1.4, 2.2.0 through before 2.2.3, 2.3.0 through before 2.3.3, or 2.4.0 through before 2.4.2 may be exposed. Risk is higher for shared ML platforms accepting untrusted workloads or tensor inputs.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation. The CVSS vector requires local access and low privileges, with high complexity. Treat it as a maintenance and tenant-isolation concern rather than an internet-scale emergency.

Researcher notes

Focus validation on version presence and trust boundaries around TensorFlow execution. The public description identifies the bug class and fixed releases but does not provide evidence of exploitation in the wild or broader product impact beyond TensorFlow.

Mitigation direction

  • Upgrade to TensorFlow 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 advisory and commit notes before changing production ML runtimes.
  • Restrict untrusted users from submitting arbitrary TensorFlow workloads on shared infrastructure.

Validation and detection

  • Inventory TensorFlow versions in applications, notebooks, containers, and ML-serving images.
  • Confirm no affected version ranges remain in deployed runtime environments.
  • Prioritize shared platforms where low-privileged users can execute TensorFlow operations.
  • Review dependency locks and base images for transitive TensorFlow inclusion.
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-125: 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-2021-29551 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-2021-29551Attack 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-125 · source CWE mapping

Out-of-bounds Read

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