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Vulnerability record · CVE-2019-15799 · published 14 November 2019

CVE-2019-15799: Zyxel gs1900-8 firmware improper privilege management vulnerability

Zyxel · Gs1900 8 Firmware

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. User accounts created through the web interface of the device, when given non-admin level privileges, have the same level of privileged access as administrators when connecting to the device via SSH (while their permissions via the web interface are in fact restricted). This allows normal users to obtain the administrative password by running the tech-support command via the CLI: this contains the encrypted passwords for all users on the device. As these passwords are encrypted using well-known and static parameters, they can be decrypted and the original passwords (including the administrator password) can be obtained.

8.8 CVSS 3.1 High EPSS 2.3% · top 17.3% CWE-269 · Improper privilege management
8.8CVSS 3.1 base score, v2 9.0
2.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
9Affected product versions listed by NVD
6References, 4 tagged exploit
17 Jun 2026Last modified by NVD

Description

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. User accounts created through the web interface of the device, when given non-admin level privileges, have the same level of privileged access as administrators when connecting to the device via SSH (while their permissions via the web interface are in fact restricted). This allows normal users to obtain the administrative password by running the tech-support command via the CLI: this contains the encrypted passwords for all users on the device. As these passwords are encrypted using well-known and static parameters, they can be decrypted and the original passwords (including the administrator password) can be obtained.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

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

References

LinkTags
https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html ExploitThird Party Advisory
https://vimeo.com/354726424 ExploitThird Party Advisory
https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml Vendor Advisory
https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html ExploitThird Party Advisory
https://vimeo.com/354726424 ExploitThird Party Advisory
https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml 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-2019-15799), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.