Cross-site scripting in Zyxel GS1900 Series Switches

Published: 2021-07-29

Security Advisory

This security advisory describes one low risk vulnerability.

1) Cross-site scripting

Risk: Low

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2021-35030

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No


The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in the CGI program. A remote authenticated attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.


Install update from vendor's website.

Vulnerable software versions

GS1900-8: 2.60

GS1900-8HP: 2.60

GS1900-10HP: 2.60

GS1900-16: 2.60

GS1900-24E: 2.60

GS1900-24EP: 2.60

GS1900-24: 2.60

GS1900-24HP: 2.60

GS1900-24HPv2: 2.60

GS1900-48: 2.60

GS1900-48HP: 2.60

GS1900-48HPv2: 2.60

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected device in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.