CVE-2021-37635Public exploit

Heap out-of-bounds write via unchecked sparse index

Published Aug 12, 2021 · Updated Aug 4, 2024

Out-of-bounds access in Google TensorFlow allows local users to read or corrupt heap data through crafted sparse-reduction inputs. SparseReduceOp computes a flat output index from each reduction group without validating group dimensions or confirming that the index is within the output tensor. Exploitation requires control of tensor indices executed by the local TensorFlow process and can disclose heap contents, corrupt memory, or crash that process.

CVSS severity7.3
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Google TensorFlow allows local users to read or corrupt heap data through crafted sparse-reduction inputs. SparseReduceOp computes a flat output index from each reduction group without validating group dimensions or confirming that the index is within the output tensor. Exploitation requires control of tensor indices executed by the local TensorFlow process and can disclose heap contents, corrupt memory, or crash that process.

The record

CVE
CVE-2021-37635
Published
Aug 12, 2021
Updated
Aug 4, 2024
Vendor
Google
Product
TensorFlow
Classifications
CWE-125, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.3.4
  2. Affected versionversion=>= 2.4.0, < 2.4.3
  3. Affected versionversion=>= 2.5.0, < 2.5.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google · TensorFlowversion=< 2.3.4; version=>= 2.4.0, < 2.4.3; version=>= 2.5.0, < 2.5.1

Published CVSS scores

3.6NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:P
7.3GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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