** UNSUPPORTED WHEN ASSIGNED ** The improper privilege management vulnerability in the command “show_allsessions” 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 attacker to obtain a logged-in administrator’s session information containing cookies on an affected device.
https://outpost24.com/blog/zyxel-nas-critical-vulnerabilities/