CVE-2022-26531: Zyxel ATP100 Firmware

High severity, CVSS 7.8. EPSS: 6.2% chance of exploitation in the next 30 days.

Multiple improper input validation flaws were identified in some CLI commands of Zyxel USG/ZyWALL series firmware versions 4.09 through 4.71, USG FLEX series firmware versions 4.50 through 5.21, ATP series firmware versions 4.32 through 5.21, VPN series firmware versions 4.30 through 5.21, NSG series firmware versions 1.00 through 1.33 Patch 4, NXC2500 firmware version 6.10(AAIG.3) and earlier versions, NAP203 firmware version 6.25(ABFA.7) and earlier versions, NWA50AX firmware version 6.25(ABYW.5) and earlier versions, WAC500 firmware version 6.30(ABVS.2) and earlier versions, and WAX510D firmware version 6.30(ABTF.2) and earlier versions, that could allow a local authenticated attacker to cause a buffer overflow or a system crash via a crafted payload.

Affected products

Zyxel ATP100 Firmware: from 4.32, up to and including 5.21
Zyxel ATP100W Firmware: from 4.32, up to and including 5.21
Zyxel ATP200 Firmware: from 4.32, up to and including 5.21
Zyxel ATP500 Firmware: from 4.32, up to and including 5.21
Zyxel ATP700 Firmware: from 4.32, up to and including 5.21
Zyxel ATP800 Firmware: from 4.32, up to and including 5.21
Zyxel NAP203 Firmware: up to and including 6.25\(abfa.7\)
Zyxel NAP303 Firmware: up to and including 6.25\(abex.7\)
Zyxel NAP353 Firmware: up to and including 6.25\(abey.7\)
Zyxel NSG100 Firmware: from 1.00, before 1.33 (fixed in 1.33); version 1.33 only
Zyxel NSG300 Firmware: from 1.00, before 1.33 (fixed in 1.33); version 1.33 only
Zyxel NSG50 Firmware: from 1.00, before 1.33 (fixed in 1.33); version 1.33 only
Zyxel NWA110AX Firmware: up to and including 6.30\(abtg.2\)
Zyxel NWA1123-Ac-Hd Firmware: up to and including 6.25\(abin.6\)
Zyxel NWA1123-Ac-Pro Firmware: up to and including 6.25\(abhd.7\)
Zyxel NWA1123ACV3 Firmware: up to and including 6.30\(abvt.2\)
Zyxel NWA1302-Ac Firmware: up to and including 6.25\(abku.6\)
Zyxel NWA210AX Firmware: up to and including 6.30\(abtd.2\)
Zyxel NWA50AX Firmware: up to and including 6.25\(abyw.5\)
Zyxel NWA5123-Ac-Hd Firmware: up to and including 6.25\(abim.6\)
Zyxel NWA55AXE Firmware: up to and including 6.25\(abzl.5\)
Zyxel NWA90AX Firmware: up to and including 6.27\(accv.2\)
Zyxel NXC2500 Firmware: up to and including 6.10\(aaig.3\)
Zyxel NXC5500 Firmware: up to and including 6.10\(aaos.3\)
Zyxel USG200 Firmware: from 4.09, up to and including 4.71
and 40 more

Published 2022-05-24. Last modified 2026-06-17.