CVE-2021-47854 | DD-WRT version 45723 contains a buffer overflow vulnerabilit… | CVSS 9.8 CRITICAL

Description

DD-WRT version 45723 contains a buffer overflow vulnerability in the UPNP network discovery service that allows remote attackers to potentially execute arbitrary code. Attackers can send crafted M-SEARCH packets with oversized UUID payloads to trigger buffer overflow conditions on the target device.

Metadata

CVE ID: CVE-2021-47854
State: PUBLISHED
Assigner: VulnCheck
Reserved: 2026-01-14 17:11 UTC
Published: 2026-01-21 17:27 UTC
Last updated: 2026-07-28 01:47 UTC
Primary CWE: CWE-120
Buffer Copy without Checking Size of Input ('Classic Buffer …
Vendor / Product: embeDD GmbH / DD-WRT
Sources: cve.org · NVD

Severity & Metrics

9.8 CRITICAL CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC — CISA Coordinator

Exploitation: PoC
Automatable: yes
Tech. Impact: total

Affected products (1)

Vendor	Product	Platform	Versions
embeDD GmbH	DD-WRT	—	45723

Weakness (CWE)

CWE	Source	Description
CWE-120	cna	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS scores (2)

Score	Severity	Version	Source	Vector
9.8	CRITICAL	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.7	HIGH	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References (5)

ExploitDB-49730 https://www.exploit-db.com/exploits/49730
DD-WRT Official Vendor Homepage https://dd-wrt.com/
DD-WRT Software Download Repository https://download1.dd-wrt.com/dd-wrtv2/downloads/betas/2021/
SSD Security Advisory for DD-WRT UPNP Buffer Overflow https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/
VulnCheck Advisory: DD-WRT 45723 - UPNP Buffer Overflow https://www.vulncheck.com/advisories/dd-wrt-upnp-buffer-overflow