CVE-2021-20862 Missing authorization in ELECOM routers

Medium 4.3 Published 1 Dec 2021 Updated 3 Aug 2024

Network-adjacent attackers can bypass access restrictions to obtain CSRF tokens and modify router settings without authentication.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2021-20862?

CVE-2021-20862 is a medium-severity missing authorization vulnerability in ELECOM routers, published on 1 Dec 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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 obtain anti-CSRF tokens and change the product's settings via unspecified vectors.

Which versions are affected by CVE-2021-20862?

It affects 14 products.

Products include Elecom Edwrc-2533gst2 Firmware, Elecom Wrc-1167gst2 Firmware, Elecom Wrc-1167gst2a Firmware, Elecom Wrc-1167gst2h Firmware, Elecom Wrc-1750gs Firmware, Elecom Wrc-1750gsv Firmware and 8 more.

How do I fix CVE-2021-20862?

No fix has been published for CVE-2021-20862 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2021-20862 being exploited?

There is no known exploitation of CVE-2021-20862 in the wild and no public exploit code.

Sources

Also known as GHSA-r89h-r4w4-jr4p.