Vulnerability identifier: #VU55434

Vulnerability 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]

CVE-ID: CVE-2021-35030

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
GS1900-8
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-8HP
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-10HP
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-16
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-24E
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-24EP
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-24
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-24HP
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-24HPv2
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-48
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-48HP
Hardware solutions / Routers & switches, VoIP, GSM, etc
GS1900-48HPv2
Hardware solutions / Routers & switches, VoIP, GSM, etc

Vendor: ZyXEL Communications Corp.

Description

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.

Mitigation
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

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External links
http://www.zyxel.com/support/Zyxel_security_advisory_for_XSS_vulnerability_of_GS1900_series_switches.shtml

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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