Vulnerability identifier: #VU86615

Vulnerability risk: Low

CVSSv3.1: 5 [CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-6399

CWE-ID: CWE-134

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
ATP series
Hardware solutions / Routers for home users
USG FLEX series
Client/Desktop applications / Antivirus software/Personal firewalls
USG FLEX 50W
Hardware solutions / Firmware
USG20W-VPN
Hardware solutions / Firmware

Vendor: ZyXEL Communications Corp.

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a format string error. A remote user on the local network can supply a specially crafted input that contains format string specifiers and cause a denial of service condition on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ATP series: 5.10 - 5.37 Patch 1

USG FLEX series: 5.10 - 5.37 Patch 1

USG FLEX 50W: 5.10 - 5.37 Patch 1

USG20W-VPN: 5.10 - 5.37 Patch 1

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External links
http://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.