What is CVE-2021-20864?

CVE-2021-20864 is a high-severity vulnerability in Elecom Edwrc-2533gst2. CVSS score: 8.8/10. Published 2021-12-01.

How severe is CVE-2021-20864?

High severity. CVSS v3 base score is 8.8 out of 10.

Vulnerability in Elecom Edwrc-2533gst2

CVE-2021-20864

Improper access control vulnerability in ELECOM routers (WRC-1167GST2 firmware v1.25 and prior, WRC-1167GST2A firmware v1.25 and prior, WRC-1167GST2H firmware v1.25 and prior, WRC-2533GS2-B firmware v1.52 and prior, WRC-2533GS2-W firmware v1.52 and prior, WRC-1750GS firmware v1.03 and prior, WRC-1750GSV firmware v2.11 and prior, WRC-1900GST firmware v1.03 and prior, WRC-2533GST firmware v1.03 and prior, WRC-2533GSTA firmware v1.03 and prior, WRC-2533GST2 firmware v1.25 and prior, WRC-2533GST2SP firmware v1.25 and prior, WRC-2533GST2-G firmware v1.25 and prior, and EDWRC-2533GST2 firmware v1.25 and prior) allows a network-adjacent unauthenticated attacker to bypass access restriction, and to start the telnet service and execute an arbitrary OS command via unspecified vectors.

Published 2021-12-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (41.8th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 41.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

References

www.elecom.co.jp/news/security/20211130-01/ (Vendor Advisory)
jvn.jp/en/vu/JVNVU94527926/index.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20864?: CVE-2021-20864 is a high-severity vulnerability in Elecom Edwrc-2533gst2. CVSS score: 8.8/10. Published 2021-12-01.
How severe is CVE-2021-20864?: High severity. CVSS v3 base score is 8.8 out of 10.