CVE-2023-4398

HIGH

Zyxel ATP/USG FLEX/USG20(W)-VPN <5.37 - DoS

Title source: llm

Description

An integer overflow vulnerability in the source code of the QuickSec IPSec toolkit used in the VPN feature of the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, and VPN series firmware versions 4.30 through 5.37, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions on an affected device by sending a crafted IKE packet.

References (1)

Core 1

Core References

Vendor Advisory vendor-advisory

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps

Scores

CVSS v3 7.5

EPSS 0.0019

EPSS Percentile 40.9%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-190

Status published

Products (1)

zyxel/zld 4.32 - 5.37

Published Nov 28, 2023

Tracked Since Feb 18, 2026