No exploitation reported

CVE-2021-20716

No exploitation reported by the sources we read.

Published2021-04-28

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Hidden functionality in multiple Buffalo network devices (BHR-4RV firmware Ver.2.55 and prior, FS-G54 firmware Ver.2.04 and prior, WBR2-B11 firmware Ver.2.32 and prior, WBR2-G54 firmware Ver.2.32 and prior, WBR2-G54-KD firmware Ver.2.32 and prior, WBR-B11 firmware Ver.2.23 and prior, WBR-G54 firmware Ver.2.23 and prior, WBR-G54L firmware Ver.2.20 and prior, WHR2-A54G54 firmware Ver.2.25 and prior, WHR2-G54 firmware Ver.2.23 and prior, WHR2-G54V firmware Ver.2.55 and prior, WHR3-AG54 firmware Ver.2.23 and prior, WHR-G54 firmware Ver.2.16 and prior, WHR-G54-NF firmware Ver.2.10 and prior, WLA2-G54 firmware Ver.2.24 and prior, WLA2-G54C firmware Ver.2.24 and prior, WLA-B11 firmware Ver.2.20 and prior, WLA-G54 firmware Ver.2.20 and prior, WLA-G54C firmware Ver.2.20 and prior, WLAH-A54G54 firmware Ver.2.54 and prior, WLAH-AM54G54 firmware Ver.2.54 and prior, WLAH-G54 firmware Ver.2.54 and prior, WLI2-TX1-AG54 firmware Ver.2.53 and prior, WLI2-TX1-AMG54 firmware Ver.2.53 and prior, WLI2-TX1-G54 firmware Ver.2.20 and prior, WLI3-TX1-AMG54 firmware Ver.2.53 and prior, WLI3-TX1-G54 firmware Ver.2.53 and prior, WLI-T1-B11 firmware Ver.2.20 and prior, WLI-TX1-G54 firmware Ver.2.20 and prior, WVR-G54-NF firmware Ver.2.02 and prior, WZR-G108 firmware Ver.2.41 and prior, WZR-G54 firmware Ver.2.41 and prior, WZR-HP-G54 firmware Ver.2.41 and prior, WZR-RS-G54 firmware Ver.2.55 and prior, and WZR-RS-G54HP firmware Ver.2.55 and prior) allows a remote attacker to enable the debug option and to execute arbitrary code or OS commands, change the configuration, and cause a denial of service (DoS) condition.

Timeline

dates in UTC

2021-04-2801:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-20716?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20716?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Buffalo bhr-4rv firmwareversion to verify

Branch	Affected	Fixed in	Source
2.55	≤ 2.55	no fix published	NVD

Buffalo fs-g54 firmwareversion to verify

Branch	Affected	Fixed in	Source
2.4	≤ 2.04	no fix published	NVD

Buffalo wbr-b11 firmwareversion to verify

Branch	Affected	Fixed in	Source
2.23	≤ 2.23	no fix published	NVD

32 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

www.buffalo.jpVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.010read 2026-10-23
FIRST EPSSEPSS score3.2 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2021-04-28
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-20716?

Is CVE-2021-20716 actively exploited?

Active exploitation of CVE-2021-20716 has not been confirmed. Its EPSS score was 3.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-20716?

CVE-2021-20716 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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