CVE-2021-20855 Cross-site scripting in ELECOM LAN routers

Medium 5.4 Published Updated

Remote authenticated attackers can inject arbitrary scripts into ELECOM LAN routers, potentially compromising user sessions or device integrity.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Over the internet
Victim action needed
A user has to click or open something
Fix
None listed

What is CVE-2021-20855?

CVE-2021-20855 is a medium-severity cross-site scripting vulnerability in ELECOM LAN routers, published on 1 Dec 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

Cross-site scripting vulnerability in ELECOM LAN routers (WRH-733GBK firmware v1.02.9 and prior and WRH-733GWH firmware v1.02.9 and prior) allows a remote authenticated attacker to inject an arbitrary script via unspecified vectors.

Weakness: CWE-79

Which versions are affected by CVE-2021-20855?

It affects 2 products.

Products include Elecom Wrh-733gbk Firmware, Elecom Wrh-733gwh Firmware.

How do I fix CVE-2021-20855?

No fix has been published for CVE-2021-20855 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-20855 being exploited?

There is no known exploitation of CVE-2021-20855 in the wild and no public exploit code.

Sources

Also known as GHSA-9cr9-j2r9-7m87.

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