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Fencer Intel
high 7.5

CVE-2019-15801 json

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.

published 6y ago modified 4mo ago also EUVD-2019-6720

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. The firmware image contains encrypted passwords that are used to authenticate users wishing to access a diagnostics or password-recovery menu. Using the hardcoded cryptographic key found elsewhere in the firmware, these passwords can be decrypted. This is related to fds_sys_passDebugPasswd_ret() and fds_sys_passRecoveryPasswd_ret() in libfds.so.0.0.

Patch / fix

  • zyxel gs1900-8_firmware 2.50\(aahh.0\)c0
  • zyxel gs1900-8hp_firmware 2.50\(aahi.0\)c0
  • zyxel gs1900-10hp_firmware 2.50\(aazi.0\)c0
  • zyxel gs1900-16_firmware 2.50\(aahj.0\)c0
  • zyxel gs1900-24e_firmware 2.50\(aahk.0\)c0
  • zyxel gs1900-24_firmware 2.50\(aahl.0\)c0
  • zyxel gs1900-24hp_firmware 2.50\(aahm.0\)c0
  • zyxel gs1900-48_firmware 2.50\(aahn.0\)c0
  • zyxel gs1900-48hp_firmware 2.50\(aaho.0\)c0

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Exploit prediction

1.49% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • jasper.la https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-798 Use of Hard-coded Credentials

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.