CVE-2021-20716

9.8 CRITICAL 3% exploit odds Fix listed Code execution Device

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 3.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-04-28 01:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:34 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 3.2% in the next 30 days (EPSS).
Severity: 9.8 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-04-28 01:15 UTC
Last modified: 2026-06-17 03:34 UTC
Exploit probability: 3.2% · EPSS, next 30 days
Record status: Modified

Affected

Buffalo bhr-4rv Firmware ≤ 2.55
Buffalo fs-g54 Firmware ≤ 2.04
Buffalo wbr2-b11 Firmware ≤ 2.32
Buffalo wbr2-g54 Firmware ≤ 2.32
Buffalo wbr2-g54-kd Firmware ≤ 2.32
Buffalo wbr-b11 Firmware ≤ 2.23
Buffalo wbr-g54 Firmware ≤ 2.23
Buffalo wbr-g54l Firmware ≤ 2.20

Attack profile CVSS 3.1 · 9.8

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-20716.md and follow it. Check whether this project is affected by CVE-2021-20716. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record