{"cve":"CVE-2019-15803","nvd":{"published":"2019-11-14T21:15:11.890","modified":"2026-06-17T02:21:06.443","status":"Modified","description":"An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Through an undocumented sequence of keypresses, undocumented functionality is triggered. A diagnostics shell is triggered via CTRL-ALT-t, which prompts for the password returned by fds_sys_passDebugPasswd_ret(). The firmware contains access control checks that determine if remote users are allowed to access this functionality. The function that performs this check (fds_sys_remoteDebugEnable_ret in libfds.so) always return TRUE with no actual checks performed. The diagnostics menu allows for reading/writing arbitrary registers and various other configuration parameters which are believed to be related to the network interface chips.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-287"],"references":["https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html","https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml","https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html","https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml"],"products":["zyxel:gs1900-10hp_firmware","zyxel:gs1900-16_firmware","zyxel:gs1900-24_firmware","zyxel:gs1900-24e_firmware","zyxel:gs1900-24hp_firmware","zyxel:gs1900-48_firmware","zyxel:gs1900-48hp_firmware","zyxel:gs1900-8_firmware","zyxel:gs1900-8hp_firmware"],"source":"nvd","synced_at":"2026-10-19T20:59:25.448946135+00:00"},"epss":{"cve":"CVE-2019-15803","score":0.01323,"percentile":0.70916,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}