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CVE Record

CVE-2021-29613: Incomplete validation in `tf.raw_ops.CTCLoss`

TensorFlow is an end-to-end open source platform for machine learning. Incomplete validation in `tf.raw_ops.CTCLoss` allows an attacker to trigger an OOB read from heap. The fix will be included in TensorFlow 2.5.0. We will also cherrypick these commits 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.

MediumCVSS 6.3Not KEV-listedUpdated
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-29613 affects TensorFlow’s CTCLoss operation. A user able to run or influence TensorFlow workloads could trigger an out-of-bounds heap read due to incomplete validation. The practical concern is integrity and availability impact in ML training or serving environments using affected TensorFlow versions.

Executive priority

Schedule remediation in the normal security patch cycle, faster for shared or user-facing ML infrastructure. There is no source-provided evidence of active exploitation, but affected versions can create integrity and availability risk when untrusted workloads are allowed.

Technical view

The issue is incomplete validation in `tf.raw_ops.CTCLoss`, allowing an out-of-bounds heap read. CVSS 3.1 is 6.3 with local attack vector, high complexity, low privileges, no user interaction, and high integrity and availability impact. TensorFlow fixed it in 2.5.0 and planned supported-branch backports.

Likely exposure

Exposure is most likely where affected TensorFlow versions run untrusted or user-influenced ML inputs, models, notebooks, training jobs, or service workloads. Confirm versions matching `<2.1.4`, `2.2.0-2.2.2`, `2.3.0-2.3.2`, or `2.4.0-2.4.1`.

Exploitation context

The source bundle does not show CISA KEV listing or cited evidence of active exploitation. Attack requirements are non-trivial: local access, low privileges, and high complexity. Treat this as important for shared ML platforms and lower urgency for isolated trusted-only workloads.

Researcher notes

Evidence is limited to the CVE record, TensorFlow advisory, and fix commits. The advisory names the vulnerable operation and affected version branches but the bundle does not provide exploit details or runtime detection indicators. Validate by version and workload reachability.

Mitigation direction

  • Upgrade TensorFlow to 2.5.0 or later where feasible.
  • For supported older branches, use 2.4.2, 2.3.3, 2.2.3, or 2.1.4.
  • Check TensorFlow’s advisory before relying on branch-specific remediation.
  • Reduce ability for untrusted users to run arbitrary TensorFlow workloads.
  • Prioritize shared notebooks, model-serving hosts, CI training runners, and multi-tenant ML environments.

Validation and detection

  • Inventory TensorFlow package versions across applications, containers, notebooks, and training images.
  • Flag versions matching the affected ranges from the CVE source bundle.
  • Search code and model pipelines for use of `tf.raw_ops.CTCLoss`.
  • Confirm upgraded environments use a fixed TensorFlow release.
  • Review ML platforms for untrusted users or inputs reaching TensorFlow execution paths.
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-665: Exact CWE lookup

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cve · low confidence lookup

CVE-2021-29613 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
Medium
CVSS
6.3 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:H/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
6.3CVSS 3.1MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H15.2Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.3Medium
CVSS 3.1 vector shape for CVE-2021-29613Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:H/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< 2.1.4, >= 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-665 · source CWE mapping

Improper Initialization

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