CVE-2022-26531

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

6.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2022-05-24 06:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:35 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 6.4% in the next 30 days (EPSS).
• Severity: 6.1 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2022-05-24 06:15 UTC

Last modified

2026-06-17 04:35 UTC

Exploit probability

6.4% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Zyxel vpn100 Firmware ≤ 5.21
• Zyxel vpn1000 Firmware ≤ 5.21
• Zyxel vpn300 Firmware ≤ 5.21
• Zyxel vpn50 Firmware ≤ 5.21
• Zyxel atp100 Firmware ≤ 5.21
• Zyxel atp100w Firmware ≤ 5.21
• Zyxel atp200 Firmware ≤ 5.21
• Zyxel atp500 Firmware ≤ 5.21

Attack profile CVSS 3.1 · 6.1

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2022-26531.md and follow it. Check whether this project is affected by CVE-2022-26531. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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