Vulnerability Monitor

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CVE-2019-9955

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.

Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 6.1, indicating it can be exploited remotely over the network with relatively low complexity though user interaction is required and does not require pre-existing privileges . The vulnerability impacts limited data confidentiality, limited integrity, for affected systems. Impacting 42 products from zyxel, from zyxel, from zyxel and 39 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

First disclosed in 2019, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.

Published

2019-04-22T20:29:00.447

Last Modified

2024-11-21T04:52:39.943

Status

Modified

Source

[email protected]

Severity

CVSSv3.0: 6.1 (MEDIUM)

CVSSv2 Vector

AV:N/AC:M/Au:N/C:N/I:P/A:N

Access Vector: NETWORK
Access Complexity: MEDIUM
Authentication: NONE
Confidentiality Impact: NONE
Integrity Impact: PARTIAL
Availability Impact: NONE

Exploitability Score

8.6

Impact Score

2.9

Weaknesses

Type: Primary
CWE-79

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Operating System	zyxel	atp200_firmware	4.31	Yes
Hardware	zyxel	atp200	-	No
Operating System	zyxel	atp500_firmware	4.31	Yes
Hardware	zyxel	atp500	-	No
Operating System	zyxel	atp800_firmware	4.31	Yes
Hardware	zyxel	atp800	-	No
Operating System	zyxel	usg20-vpn_firmware	4.31	Yes
Hardware	zyxel	usg20-vpn	-	No
Operating System	zyxel	usg20w-vpn_firmware	4.31	Yes
Hardware	zyxel	usg20w-vpn	-	No
Operating System	zyxel	usg40_firmware	4.31	Yes
Hardware	zyxel	usg40	-	No
Operating System	zyxel	usg40w_firmware	4.31	Yes
Hardware	zyxel	usg40w	-	No
Operating System	zyxel	usg60_firmware	4.31	Yes
Hardware	zyxel	usg60	-	No
Operating System	zyxel	usg60w_firmware	4.31	Yes
Hardware	zyxel	usg60w	-	No
Operating System	zyxel	usg110_firmware	4.31	Yes
Hardware	zyxel	usg110	-	No
Operating System	zyxel	usg210_firmware	4.31	Yes
Hardware	zyxel	usg210	-	No
Operating System	zyxel	usg310_firmware	4.31	Yes
Hardware	zyxel	usg310	-	No
Operating System	zyxel	usg1100_firmware	4.31	Yes
Hardware	zyxel	usg1100	-	No
Operating System	zyxel	usg1900_firmware	4.31	Yes
Hardware	zyxel	usg1900	-	No
Operating System	zyxel	usg2200-vpn_firmware	4.31	Yes
Hardware	zyxel	usg2200-vpn	-	No
Operating System	zyxel	zywall_110_firmware	4.31	Yes
Hardware	zyxel	zywall_110	-	No
Operating System	zyxel	zywall_310_firmware	4.31	Yes
Hardware	zyxel	zywall_310	-	No
Operating System	zyxel	zywall_1100_firmware	4.31	Yes
Hardware	zyxel	zywall_1100	-	No
Operating System	zyxel	vpn50_firmware	-	Yes
Hardware	zyxel	vpn50	-	No
Operating System	zyxel	vpn100_firmware	-	Yes
Hardware	zyxel	vpn100	-	No
Operating System	zyxel	vpn300_firmware	-	Yes
Hardware	zyxel	vpn300	-	No

References

http://packetstormsecurity.com/files/152525/Zyxel-ZyWall-Cross-Site-Scripting.html Exploit, Third Party Advisory, VDB Entry ([email protected])
http://seclists.org/fulldisclosure/2019/Apr/22 Mailing List, Third Party Advisory ([email protected])
https://www.exploit-db.com/exploits/46706/ Exploit, Third Party Advisory, VDB Entry ([email protected])
https://www.securitymetrics.com/blog/Zyxel-Devices-Vulnerable-Cross-Site-Scripting-Login-page Patch, Third Party Advisory ([email protected])
https://www.zyxel.com/support/reflected-cross-site-scripting-vulnerability-of-firewalls.shtml Vendor Advisory ([email protected])
http://packetstormsecurity.com/files/152525/Zyxel-ZyWall-Cross-Site-Scripting.html Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
http://seclists.org/fulldisclosure/2019/Apr/22 Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/46706/ Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.securitymetrics.com/blog/Zyxel-Devices-Vulnerable-Cross-Site-Scripting-Login-page Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.zyxel.com/support/reflected-cross-site-scripting-vulnerability-of-firewalls.shtml Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For zyxel's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.