CVE-2022-34747

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-09-06 · updated 2026-06-17
Weakness: CWE-134

Description

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

How to fix

Upgrade to a fixed version: Zyxel NAS326 firmware 5.21\(aazf.12\)c0. Check the vendor advisory for mitigations.

References

https://www.zyxel.com/support/Zyxel-security-advisory-for-format-string-vulnerability-in-NAS.shtml
https://www.zyxel.com/support/Zyxel-security-advisory-for-format-string-vulnerability-in-NAS.shtml

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