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CVE Record

CVE-2021-29546: Division by 0 in `QuantizedBiasAdd`

TensorFlow is an end-to-end open source platform for machine learning. An attacker can trigger an integer division by zero undefined behavior in `tf.raw_ops.QuantizedBiasAdd`. This is because the implementation of the Eigen kernel(https://github.com/tensorflow/tensorflow/blob/61bca8bd5ba8a68b2d97435ddfafcdf2b85672cd/tensorflow/core/kernels/quantization_utils.h#L812-L849) does a division by the number of elements of the smaller input (based on shape) without checking that this is not zero. 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-2021-29546 is a low-severity TensorFlow flaw where a crafted use of QuantizedBiasAdd can cause a division-by-zero condition. The expected impact is limited availability disruption, not data theft or privilege escalation, but shared ML platforms should still patch affected TensorFlow versions.

Executive priority

Treat this as routine patching unless TensorFlow is exposed through multi-tenant or user-submitted ML workloads. It is low severity, but availability issues in shared compute or model-serving environments can still disrupt business operations.

Technical view

TensorFlow's Eigen kernel for tf.raw_ops.QuantizedBiasAdd divided by the element count of the smaller shaped input without checking for zero. This can trigger integer division by zero undefined behavior. CVSS 3.1 is 2.5: local attack vector, high complexity, low privileges, and low availability impact only.

Likely exposure

Exposure is most likely where affected TensorFlow versions run workloads from low-privileged or untrusted users, especially shared notebooks, ML pipelines, or services that execute submitted TensorFlow graphs. The bundle lists TensorFlow versions before 2.1.4 and specific 2.2.x, 2.3.x, and 2.4.x ranges as affected.

Exploitation context

The provided sources do not show active exploitation, and the CVE is not marked in KEV. Exploitation requires local access, low privileges, and high attack complexity. The supported impact is availability degradation through a crash or undefined behavior, not confidentiality or integrity compromise.

Researcher notes

The core weakness is CWE-369 in QuantizedBiasAdd shape handling. Evidence supports a division by the smaller input's element count without a zero check. No exploit code, real-world exploitation, or broader product impact is provided in the source bundle.

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 those branches are required.
  • Move older unsupported TensorFlow releases to a supported patched release.
  • Review TensorFlow's advisory and fix commit for vendor-specific remediation details.

Validation and detection

  • Inventory TensorFlow versions in production, notebooks, CI, and model-serving environments.
  • Flag versions below 2.1.4 and affected 2.2.x, 2.3.x, and 2.4.x ranges.
  • Confirm patched deployments report TensorFlow 2.5.0 or the applicable fixed branch version.
  • Check whether untrusted users can execute TensorFlow workloads on shared systems.
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-369: 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-2021-29546 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-2021-29546Attack 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-369 · source CWE mapping

Divide By Zero

Divide By Zero represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.