Vulnerability Monitor

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CVE-2019-12581

A reflective Cross-site scripting (XSS) vulnerability in the free_time_failed.cgi CGI program in selected Zyxel ZyWall, USG, and UAG devices allows remote attackers to inject arbitrary web script or HTML via the err_msg 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 18 products from zyxel, from zyxel, from zyxel and 15 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

2019-06-27T15:15:09.170

Last Modified

2024-11-21T04:23:08.050

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	uag2100_firmware	≤ 4.18\(aaiz.1\)c0	Yes
Hardware	zyxel	uag2100	-	No
Operating System	zyxel	uag4100_firmware	≤ 4.18\(aatd.1\)c0	Yes
Hardware	zyxel	uag4100	-	No
Operating System	zyxel	uag5100_firmware	≤ 4.18\(aapn.1\)c0	Yes
Hardware	zyxel	uag5100	-	No
Operating System	zyxel	usg110_firmware	≤ 4.30	Yes
Hardware	zyxel	usg110	-	No
Operating System	zyxel	usg210_firmware	≤ 4.30	Yes
Hardware	zyxel	usg210	-	No
Operating System	zyxel	usg310_firmware	≤ 4.30	Yes
Hardware	zyxel	usg310	-	No
Operating System	zyxel	usg1100_firmware	≤ 4.30	Yes
Hardware	zyxel	usg1100	-	No
Operating System	zyxel	usg1900_firmware	≤ 4.30	Yes
Hardware	zyxel	usg1900	-	No
Operating System	zyxel	usg2200-vpn_firmware	≤ 4.30	Yes
Hardware	zyxel	usg2200-vpn	-	No

References

https://n-thumann.de/blog/zyxel-gateways-missing-access-control-in-account-generator-xss/ Exploit, Third Party Advisory ([email protected])
https://sec-consult.com/en/blog/advisories/reflected-cross-site-scripting-in-zxel-zywall/index.html Exploit, Patch, Third Party Advisory ([email protected])
https://www.zyxel.com/support/vulnerabilities-related-to-the-Free-Time-feature.shtml Patch, Vendor Advisory ([email protected])
https://www.zyxel.com/us/en/ Vendor Advisory ([email protected])
https://n-thumann.de/blog/zyxel-gateways-missing-access-control-in-account-generator-xss/ Exploit, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://sec-consult.com/en/blog/advisories/reflected-cross-site-scripting-in-zxel-zywall/index.html Exploit, Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.zyxel.com/support/vulnerabilities-related-to-the-Free-Time-feature.shtml Patch, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.zyxel.com/us/en/ 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.