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Fencer Intel
medium 5.9

CVE-2019-15802 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-2019-6721

cvss
5.9
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 hashes and encrypts passwords using a hardcoded cryptographic key in sal_util_str_encrypt() in libsal.so.0.0. The parameters (salt, IV, and key data) are used to encrypt and decrypt all passwords using AES256 in CBC mode. With the parameters known, all previously encrypted passwords can be decrypted. This includes the passwords that are part of configuration backups or otherwise embedded as part of the firmware.

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

1.50% 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 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/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.