What is CVE-2021-20711?

CVE-2021-20711 is a critical-severity vulnerability in Nec Aterm Wg2600hs, classified under OS Command Injection. CVSS score: 9.8/10. Published 2021-04-26.

How severe is CVE-2021-20711?

Critical severity. CVSS v3 base score is 9.8 out of 10.

RCE in Nec Aterm Wg2600hs

CVE-2021-20711

Aterm WG2600HS firmware Ver1.5.1 and earlier allows an attacker to execute arbitrary OS commands via unspecified vectors.

Vulnerability class: Command Injection (OS Command Injection)

Published 2021-04-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.014 (70.6th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 70.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Nec Aterm Wg2600hs
Nec Aterm Wg2600hs Firmware
Nec Corporation Aterm Wg2600hs — versions firmware Ver1.5.1 and earlier

Weakness classification (CWE)

CWE-78 — OS Command Injection

References

jpn.nec.com/security-info/secinfo/nv21-010.html (Mitigation, Vendor Advisory)
jvn.jp/en/jp/JVN29739718/index.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20711?: CVE-2021-20711 is a critical-severity vulnerability in Nec Aterm Wg2600hs, classified under OS Command Injection. CVSS score: 9.8/10. Published 2021-04-26.
How severe is CVE-2021-20711?: Critical severity. CVSS v3 base score is 9.8 out of 10.