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CVE Record

CVE-2021-29548: Division by 0 in `QuantizedBatchNormWithGlobalNormalization`

TensorFlow is an end-to-end open source platform for machine learning. An attacker can cause a runtime division by zero error and denial of service in `tf.raw_ops.QuantizedBatchNormWithGlobalNormalization`. This is because the implementation(https://github.com/tensorflow/tensorflow/blob/55a97caa9e99c7f37a0bbbeb414dc55553d3ae7f/tensorflow/core/kernels/quantized_batch_norm_op.cc) does not validate all constraints specified in the op's contract(https://www.tensorflow.org/api_docs/python/tf/raw_ops/QuantizedBatchNormWithGlobalNormalization). 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-2021-29548 is a low-severity TensorFlow denial-of-service issue. A user able to trigger a specific raw TensorFlow operation can cause a division-by-zero runtime error, disrupting availability but not exposing or altering data.

Executive priority

Treat this as routine patching unless the organization offers shared or user-extensible TensorFlow execution. The main business risk is localized workload disruption, not data compromise or broad remote compromise based on available sources.

Technical view

The flaw is CWE-369 in tf.raw_ops.QuantizedBatchNormWithGlobalNormalization. TensorFlow did not validate all constraints required by the operation contract, allowing a division by zero and process-level denial of service in affected supported releases.

Likely exposure

Exposure is most likely in ML services, notebooks, pipelines, or products running affected TensorFlow versions where low-privileged local users or submitted workloads can invoke the vulnerable raw op.

Exploitation context

The CVE is not listed as KEV, and the provided sources do not report active exploitation. CVSS indicates local access, high attack complexity, low privileges required, no user interaction, and only low availability impact.

Researcher notes

Focus analysis on version exposure and reachable use of QuantizedBatchNormWithGlobalNormalization. The advisory attributes impact to missing validation against the op contract; review the linked fix for exact validation changes when assessing forks or backports.

Mitigation direction

  • Upgrade TensorFlow to 2.5.0 or a fixed supported backport release.
  • Use TensorFlow 2.4.2, 2.3.3, 2.2.3, or 2.1.4 where pinned to older branches.
  • Check TensorFlow’s advisory for any branch-specific guidance before remediation.
  • Restrict untrusted users from running arbitrary TensorFlow operations in shared environments.

Validation and detection

  • Inventory deployed TensorFlow versions in applications, images, notebooks, and training workers.
  • Flag versions below 2.1.4 and vulnerable 2.2.x, 2.3.x, and 2.4.x ranges.
  • Identify services that expose TensorFlow execution to untrusted users or submitted workloads.
  • Confirm upgraded environments use fixed TensorFlow packages before returning shared workloads to service.
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-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-2021-29548 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-2021-29548Attack 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.