CVE-2019-15803
mediumpriority · track · 36EPSS 0.013 · 71 %ileEURUUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.4–9.1
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (19)
Products and version ranges known to be affected.
- zyxel gs1900-10hp firmware< 2.50\(aazi.0\)c0nvdUScpe:2.3:o:zyxel:gs1900-10hp_firmware:*:*:*:*:*:*:*:*
- zyxel gs1900-24hp firmware< 2.50\(aahm.0\)c0nvdUScpe:2.3:o:zyxel:gs1900-24hp_firmware:*:*:*:*:*:*:*:*
- zyxel gs1900-48hp firmware< 2.50\(aaho.0\)c0nvdUScpe:2.3:o:zyxel:gs1900-48hp_firmware:*:*:*:*:*:*:*:*
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (7)
External citations — patches, advisories, analysis.
- https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.htmlcnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2019-15803cnnvd
- https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtmlcnnvd
- https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.htmlenisa_euvd
- https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtmlenisa_euvd
- https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.htmlExploitThird Party Advisorynvd
- https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtmlVendor Advisorynvd
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