How severe is CVE-2021-20637?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Logitec Corporation Lan-W300n/pr5b

CVE-2021-20637

Improper check or handling of exceptional conditions in LOGITEC LAN-W300N/PR5B allows a remote attacker to cause a denial-of-service (DoS) condition by sending a specially crafted URL.

Published 2021-02-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.010 (62.2th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 62nd percentile — 62.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: +0.000

Affected products

Logitec Corporation Lan-W300n/pr5b — versions LAN-W300N/PR5B
Logitech Lan-W300n\/pr5b
Logitech Lan-W300n\/pr5b Firmware

References

www.elecom.co.jp/news/security/20210126-01/ (Vendor Advisory)
jvn.jp/en/jp/JVN96783542/index.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20637?: CVE-2021-20637 is a medium-severity vulnerability in Logitec Corporation Lan-W300n/pr5b. CVSS score: 6.5/10. Published 2021-02-12.
How severe is CVE-2021-20637?: Medium severity. CVSS v3 base score is 6.5 out of 10.