CVE-2021-47854

Name: CVE-2021-47854
Creator: NVD / NIST
Published: 2026-01-21T18:16:15.003+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.7/10EPSS 0.97%

Last modified Jun 17, 2026

CVE-2021-47854 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. 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.. EPSS estimates a 0.97% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

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

CVSS 4.0

8.7/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.97%

57.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-120

References

Timeline

Published: Jan 21, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2021-47854?

How severe is CVE-2021-47854?

CVE-2021-47854 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.97% probability of exploitation in the next 30 days.

How do I fix CVE-2021-47854?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-47854?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST