CVE-2021-35030 Cross-site scripting in GS1900-8 Firmware

What is CVE-2021-35030?

CVE-2021-35030 is a low-severity cross-site scripting vulnerability in Zyxel GS1900-8 Firmware, published on 26 Jul 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A vulnerability was found in the CGI program in Zyxel GS1900-8 firmware version V2.60, that did not properly sterilize packet contents and could allow an authenticated, local user to perform a cross-site scripting (XSS) attack via a crafted LLDP packet.

Weakness: CWE-79

Which versions are affected by CVE-2021-35030?

It affects 12 products.

Products include Zyxel Gs1900-10hp Firmware, Zyxel Gs1900-16 Firmware, Zyxel Gs1900-24 Firmware, Zyxel Gs1900-24e Firmware, Zyxel Gs1900-24ep Firmware, Zyxel Gs1900-24hp Firmware and 6 more.

How do I fix CVE-2021-35030?

No fix has been published for CVE-2021-35030 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-2021-35030 being exploited?

There is no known exploitation of CVE-2021-35030 in the wild and no public exploit code.

Other vulnerabilities in Zyxel GS1900-8 Firmware

• CVE-2026-7273 Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Exploited High 8.8
• CVE-2019-15800 Command injection in n/a Critical 9.8
• CVE-2015-5988 Hardcoded credentials in n/a Critical 9.8
• CVE-2015-5989 Auth bypass in n/a Critical 9.8
• CVE-2019-15803 Auth bypass in n/a Critical 9.1

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-g78g-pgq7-f6cr.