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CVE Record

CVE-2021-29579: Heap buffer overflow in `MaxPoolGrad`

TensorFlow is an end-to-end open source platform for machine learning. The implementation of `tf.raw_ops.MaxPoolGrad` is vulnerable to a heap buffer overflow. The implementation(https://github.com/tensorflow/tensorflow/blob/ab1e644b48c82cb71493f4362b4dd38f4577a1cf/tensorflow/core/kernels/maxpooling_op.cc#L194-L203) fails to validate that indices used to access elements of input/output arrays are valid. Whereas accesses to `input_backprop_flat` are guarded by `FastBoundsCheck`, the indexing in `out_backprop_flat` can result in OOB access. 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-2021-29579 is a TensorFlow memory safety bug in MaxPoolGrad. A local, low-privileged user or job that can run affected TensorFlow code may cause a crash or limited availability impact. The sources do not support data theft, integrity impact, or active exploitation.

Executive priority

Treat this as routine patch management unless affected TensorFlow is exposed in shared or untrusted ML execution environments. The business risk is mainly service disruption, not confirmed compromise or data exposure.

Technical view

TensorFlow’s tf.raw_ops.MaxPoolGrad did not validate all indices before accessing arrays. input_backprop_flat access was bounds-checked, but out_backprop_flat indexing could go out of bounds, causing heap buffer overflow behavior. Affected versions are below fixed 2.1.4, 2.2.3, 2.3.3, and 2.4.2 releases.

Likely exposure

Exposure is limited to environments running the listed vulnerable TensorFlow versions and allowing users or workloads to invoke MaxPoolGrad with controlled inputs. This is most relevant to shared ML platforms, notebooks, CI jobs, or services executing untrusted TensorFlow workloads.

Exploitation context

The CVSS vector requires local access, low privileges, high attack complexity, and no user interaction. CISA KEV status is false in the provided bundle, and no cited source reports active exploitation. Impact is described as availability-only and low.

Researcher notes

The root issue is missing validation for out_backprop_flat indexing in MaxPoolGrad. The public advisory names the fixed release plan and the commit reference. Evidence does not establish practical exploitation beyond the stated local, high-complexity, low-availability CVSS profile.

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 branch pinning is required.
  • Update dependency lockfiles, containers, and ML runtime images using affected TensorFlow versions.
  • Restrict execution of untrusted TensorFlow workloads until affected runtimes are patched.
  • Check TensorFlow vendor guidance if unable to upgrade immediately.

Validation and detection

  • Inventory deployed TensorFlow package versions across code, images, notebooks, and training environments.
  • Confirm no runtime uses TensorFlow versions below the fixed branch releases.
  • Check dependency manifests and container layers for transitive TensorFlow pins.
  • Run normal ML regression tests after upgrading TensorFlow.
  • Document any exception where an affected runtime remains in use.
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-119: Exact CWE lookup

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cve · low confidence lookup

CVE-2021-29579 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-2021-29579Attack 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-119 · source CWE mapping

Improper Restriction of Operations within the Bounds of a Memory Buffer

Improper Restriction of Operations within the Bounds of a Memory Buffer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.