CVE-2022-34747: Zyxel NAS326 Firmware

Critical severity, CVSS 9.8. EPSS: 1.7% chance of exploitation in the next 30 days.

A format string vulnerability in Zyxel NAS326 firmware versions prior to V5.21(AAZF.12)C0 could allow an attacker to achieve unauthorized remote code execution via a crafted UDP packet.

Affected products

• Zyxel NAS326 Firmware: before 5.21\(aazf.12\)c0 (fixed in 5.21\(aazf.12\)c0)

Published 2022-09-06. Last modified 2026-06-17.