CVE-2021-34201Public exploit

Local process corruption via out-of-bounds global writes

Published Jun 16, 2021 · Updated Jul 9, 2026

Out-of-bounds writes in D-Link DIR-2640-US firmware 1.01B04 allow local users to corrupt process memory and crash services. The affected processes write beyond buffer bounds into global variables in their .bss sections; their names and input paths are undisclosed. An ordinary local account is required; successful writes alter process state or terminate the affected process.

CVSS severity7.1
High
EPSS probability0.54%
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 writes in D-Link DIR-2640-US firmware 1.01B04 allow local users to corrupt process memory and crash services. The affected processes write beyond buffer bounds into global variables in their .bss sections; their names and input paths are undisclosed. An ordinary local account is required; successful writes alter process state or terminate the affected process.

The record

CVE
CVE-2021-34201
Published
Jun 16, 2021
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
3.6NIST NVDAV:L/AC:L/Au:N/C:N/I:P/A:P

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.

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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-787Out-of-bounds Write
T1499.004Application 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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