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Vulnerability record · CVE-2019-12581 · published 27 June 2019

CVE-2019-12581: Zyxel uag2100 firmware cross-site scripting vulnerability

Zyxel · Uag2100 Firmware

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.

6.1 CVSS 3.0 Medium EPSS 6.4% · top 6.6% CWE-79 · Cross-site scripting
6.1CVSS 3.0 base score, v2 4.3
6.4%EPSS exploitation probability, 30 days
NoNot in CISA KEV
9Affected product versions listed by NVD
8References, 4 tagged exploit
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

9 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://n-thumann.de/blog/zyxel-gateways-missing-access-control-in-account-generator-xss/ ExploitThird Party Advisory
https://sec-consult.com/en/blog/advisories/reflected-cross-site-scripting-in-zxel-zywall/index.html ExploitPatchThird Party Advisory
https://www.zyxel.com/support/vulnerabilities-related-to-the-Free-Time-feature.shtml PatchVendor Advisory
https://www.zyxel.com/us/en/ Vendor Advisory
https://n-thumann.de/blog/zyxel-gateways-missing-access-control-in-account-generator-xss/ ExploitThird Party Advisory
https://sec-consult.com/en/blog/advisories/reflected-cross-site-scripting-in-zxel-zywall/index.html ExploitPatchThird Party Advisory
https://www.zyxel.com/support/vulnerabilities-related-to-the-Free-Time-feature.shtml PatchVendor Advisory
https://www.zyxel.com/us/en/ Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2019-12581), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.