** UNSUPPORTED WHEN ASSIGNED ** The improper privilege management vulnerability in the SUID executable binary in Zyxel NAS326 firmware versions before V5.21(AAZF.17)C0 and NAS542 firmware versions before V5.21(ABAG.14)C0 could allow an authenticated local attacker with administrator privileges to execute some system commands as the “root” user on a vulnerable device.
https://outpost24.com/blog/zyxel-nas-critical-vulnerabilities/