CVE-2021-37655

Heap OOB in `ResourceScatterUpdate` in TensorFlow

HIGH
7.3
CVSS Score
Published: August 12, 2021 at 08:25 PM UTC
Updated: June 17, 2026 at 04:00 AM UTC
2 products affected across 2 vendorsTensorflowTensorFlow

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Severity
HIGH7.3
Exploit prediction
EPSS 0.2%

Description

TensorFlow is an end-to-end open source platform for machine learning. In affected versions an attacker can trigger a read from outside of bounds of heap allocated data by sending invalid arguments to `tf.raw_ops.ResourceScatterUpdate`. The [implementation](https://github.com/tensorflow/tensorflow/blob/f24faa153ad31a4b51578f8181d3aaab77a1ddeb/tensorflow/core/kernels/resource_variable_ops.cc#L919-L923) has an incomplete validation of the relationship between the shapes of `indices` and `updates`: instead of checking that the shape of `indices` is a prefix of the shape of `updates` (so that broadcasting can happen), code only checks that the number of elements in these two tensors are in a divisibility relationship. We have patched the issue in GitHub commit 01cff3f986259d661103412a20745928c727326f. The fix will be included in TensorFlow 2.6.0. We will also cherrypick this commit on TensorFlow 2.5.1, TensorFlow 2.4.3, and TensorFlow 2.3.4, as these are also affected and still in supported range.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.3.0 ≤ v < 2.3.42.4.0 ≤ v < 2.4.32.5.02.6.0 rc02.6.0 rc12.6.0 rc2
Affected range stops below 2.3.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 2.4.3, so it looks safe — our inference, not a vendor statement
v < 2.3.4v < 2.4.3v < 2.5.1
Affected range stops below 2.3.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 2.4.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 2.5.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

7.3HIGHGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-125

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