CVE-2019-9955

Name: CVE-2019-9955
Creator: NVD / NIST
Published: 2019-04-22T20:29:00.447+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 20.95%

Last modified Jun 17, 2026

CVE-2019-9955 is a vulnerability of currently unknown severity. On Zyxel ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200-VPN, ZyWALL 110, ZyWALL 310, ZyWALL 1100 devices, the security firewall login page is vulnerable to Reflected XSS via the unsanitized 'mp_idx' parameter.. EPSS estimates a 20.95% chance of exploitation in the next 30 days.

Description

On Zyxel ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200-VPN, ZyWALL 110, ZyWALL 310, ZyWALL 1100 devices, the security firewall login page is vulnerable to Reflected XSS via the unsanitized 'mp_idx' parameter.

Metrics

EPSS Probability

20.95%

97.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Zyxel	Atp200 Firmware	4.31
Zyxel	Atp500 Firmware	4.31
Zyxel	Atp800 Firmware	4.31
Zyxel	Usg20-Vpn Firmware	4.31
Zyxel	Usg20w-Vpn Firmware	4.31
Zyxel	Usg40 Firmware	4.31
Zyxel	Usg40w Firmware	4.31
Zyxel	Usg60 Firmware	4.31
Zyxel	Usg60w Firmware	4.31
Zyxel	Usg110 Firmware	4.31
Zyxel	Usg210 Firmware	4.31
Zyxel	Usg310 Firmware	4.31
Zyxel	Usg1100 Firmware	4.31
Zyxel	Usg1900 Firmware	4.31
Zyxel	Usg2200-Vpn Firmware	4.31
Zyxel	Zywall 110 Firmware	4.31
Zyxel	Zywall 310 Firmware	4.31
Zyxel	Zywall 1100 Firmware	4.31
Zyxel	Vpn50 Firmware	All versions
Zyxel	Vpn100 Firmware	All versions
Zyxel	Vpn300 Firmware	All versions

References

http://packetstormsecurity.com/files/152525/Zyxel-ZyWall-Cross-Site-Scripting.htmlExploit, Third Party Advisory, VDB Entry
http://seclists.org/fulldisclosure/2019/Apr/22Mailing List, Third Party Advisory
https://www.exploit-db.com/exploits/46706/Exploit, Third Party Advisory, VDB Entry
https://www.securitymetrics.com/blog/Zyxel-Devices-Vulnerable-Cross-Site-Scripting-Login-pagePatch, Third Party Advisory
https://www.zyxel.com/support/reflected-cross-site-scripting-vulnerability-of-firewalls.shtmlVendor Advisory
http://packetstormsecurity.com/files/152525/Zyxel-ZyWall-Cross-Site-Scripting.htmlExploit, Third Party Advisory, VDB Entry
http://seclists.org/fulldisclosure/2019/Apr/22Mailing List, Third Party Advisory
https://www.exploit-db.com/exploits/46706/Exploit, Third Party Advisory, VDB Entry
https://www.securitymetrics.com/blog/Zyxel-Devices-Vulnerable-Cross-Site-Scripting-Login-pagePatch, Third Party Advisory
https://www.zyxel.com/support/reflected-cross-site-scripting-vulnerability-of-firewalls.shtmlVendor Advisory

Timeline

Published: Apr 22, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-9955?

How severe is CVE-2019-9955?

Severity scoring for CVE-2019-9955 is pending analysis. The EPSS model estimates a 20.95% probability of exploitation in the next 30 days.

How do I fix CVE-2019-9955?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-9955?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST