---
id: CVE-2021-34201
title: D-Link DIR-2640-US 1.01B04 is vulnerable to Buffer Overflow
summary: >-
  D-Link DIR-2640-US 1.01B04 is vulnerable to Buffer Overflow. There are
  multiple out-of-bounds vulnerabilities in some processes of D-Link
  AC2600(DIR-2640). Local ordinary users can overwrite the global variables in
  the .bss section, caus…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H'
cwe:
  - CWE-787
vendor: dlink
product: dir-2640-us_firmware
affected:
  - dir-2640-us_firmware = 1.01b04
published: '2021-06-16'
updated: '2026-07-05'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-34201'
references:
  - url: 'https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34201'
    label: cve@mitre.org
  - url: 'https://www.dlink.com/en/security-bulletin/'
    label: cve@mitre.org
  - url: 'http://d-link.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://dir-2640-us.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34201'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.dlink.com/en/security-bulletin/'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.0054
epssPercentile: 0.44352
ingestedAt: '2026-07-06T01:08:16.757Z'
---

## Overview

D-Link DIR-2640-US 1.01B04 is vulnerable to Buffer Overflow. There are multiple out-of-bounds vulnerabilities in some processes of D-Link AC2600(DIR-2640). Local ordinary users can overwrite the global variables in the .bss section, causing the process crashes or changes.

## Affected

- `dir-2640-us_firmware = 1.01b04`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.