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Vulnerability record · CVE-2021-47854 · published 21 January 2026

CVE-2021-47854: Classic buffer overflow vulnerability

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.

8.7 CVSS 4.0 High EPSS 1.1% · top 35.7% CWE-120 · Classic buffer overflow Deferred
8.7CVSS 4.0 base score
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
5References
17 Jun 2026Last modified by NVD

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.

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:

References

LinkTags
https://dd-wrt.com/
https://download1.dd-wrt.com/dd-wrtv2/downloads/betas/2021/
https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/
https://www.exploit-db.com/exploits/49730
https://www.vulncheck.com/advisories/dd-wrt-upnp-buffer-overflow

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Source: NIST National Vulnerability Database (record CVE-2021-47854), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.