NVD

CVE-2023-6764 Detail

Description

A format string vulnerability in a function of the IPSec VPN feature in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1, USG FLEX series firmware versions from 4.50 through 5.37 Patch 1, USG FLEX 50(W) series firmware versions from 4.16 through 5.37 Patch 1, and USG20(W)-VPN series firmware versions from 4.16 through 5.37 Patch 1 could allow an attacker to achieve unauthorized remote code execution by sending a sequence of specially crafted payloads containing an invalid pointer; however, such an attack would require detailed knowledge of an affected device’s memory layout and configuration.

Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

Nist CVSS score does not match with CNA score

CNA: Zyxel Corporation

Base Score: 8.1 HIGH

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

CVSS 2.0 Severity and Vector Strings:

National Institute of Standards and Technology

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024	CVE, Zyxel Corporation	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-134	Use of Externally-Controlled Format String	NIST Zyxel Corporation

Known Affected Software Configurations Switch to CPE 2.2

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Change History

6 change records found show changes

CVE Modified by CISA-ADP 6/17/2026 2:51:22 AM

Action

Type

Old Value

New Value

Added

Affected

[{"vendor":"zyxel","product":"atp_firmware","defaultStatus":"unknown","cpes":["cpe:2.3:o:zyxel:atp_firmware:-:*:*:*:*:*:*:*"],"versions":[{"version":"4.32","lessThanOrEqual":"5.37patch1","versionType":"custom","status":"affected"}]},{"vendor":"zyxel","product":"usg_flex_firmware","defaultStatus":"unknown","cpes":["cpe:2.3:o:zyxel:usg_flex_firmware:-:*:*:*:*:*:*:*"],"versions":[{"version":"4.50","lessThanOrEqual":"5.37patch1","versionType":"custom","status":"affected"}]},{"vendor":"zyxel","product":"usg_flex_50w_firmware","defaultStatus":"unknown","cpes":["cpe:2.3:o:zyxel:usg_flex_50w_firmware:-:*:*:*:*:*:*:*"],"versions":[{"version":"4.16","lessThanOrEqual":"5.37patch1","versionType":"custom","status":"affected"}]},{"vendor":"zyxel","product":"usg_20w-vpn_firmware","defaultStatus":"unknown","cpes":["cpe:2.3:o:zyxel:usg_20w-vpn_firmware:-:*:*:*:*:*:*:*"],"versions":[{"version":"4.16","lessThanOrEqual":"5.37patch1","versionType":"custom","status":"affected"}]}]

Added

SSVC

{"timestamp":"2024-03-01T05:01:05.440386Z","id":"CVE-2023-6764","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}

Initial Analysis by NIST 1/21/2025 1:36:00 PM

Action	Type	Old Value	New Value
Added	CWE		NIST CWE-134
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:atp100_firmware::::::::* versions from (including) 4.32 up to (excluding) 5.37 cpe:2.3:o:zyxel:atp100_firmware:5.37:-::::::* cpe:2.3:o:zyxel:atp100_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:atp100:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:atp100w_firmware::::::::* versions from (including) 4.32 up to (excluding) 5.37 cpe:2.3:o:zyxel:atp100w_firmware:5.37:-::::::* cpe:2.3:o:zyxel:atp100w_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:atp100w:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:atp200_firmware::::::::* versions from (including) 4.32 up to (excluding) 5.37 cpe:2.3:o:zyxel:atp200_firmware:5.37:-::::::* cpe:2.3:o:zyxel:atp200_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:atp200:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:atp500_firmware::::::::* versions from (including) 4.32 up to (excluding) 5.37 cpe:2.3:o:zyxel:atp500_firmware:5.37:-::::::* cpe:2.3:o:zyxel:atp500_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:atp500:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:atp700_firmware::::::::* versions from (including) 4.32 up to (excluding) 5.37 cpe:2.3:o:zyxel:atp700_firmware:5.37:-::::::* cpe:2.3:o:zyxel:atp700_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:atp700:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:atp800_firmware::::::::* versions from (including) 4.32 up to (excluding) 5.37 cpe:2.3:o:zyxel:atp800_firmware:5.37:-::::::* cpe:2.3:o:zyxel:atp800_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:atp800:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg20-vpn_firmware::::::::* versions from (including) 4.16 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg20-vpn_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg20-vpn_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg20-vpn:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg20w-vpn_firmware::::::::* versions from (including) 4.16 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg20w-vpn_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg20w-vpn_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg20w-vpn:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_100_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_100_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_100_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_100:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_100ax_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_100ax_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_100ax_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_100ax:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_100h_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_100h_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_100h_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_100h:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_100w_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_100w_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_100w_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_100w:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_200_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_200_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_200_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_200:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_200h_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_200h_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_200h_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_200h:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_200hp_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_200hp_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_200hp_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_200hp:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_500_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_500_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_500_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_500:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_500h_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_500h_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_500h_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_500h:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_50_firmware::::::::* versions from (including) 4.16 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_50_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_50_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_50:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_50w_firmware::::::::* versions from (including) 4.16 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_50w_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_50w_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_50w:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_700_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_700_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_700_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_700:-:::::::*
Added	CPE Configuration		AND OR cpe:2.3:o:zyxel:usg_flex_700h_firmware::::::::* versions from (including) 4.50 up to (excluding) 5.37 cpe:2.3:o:zyxel:usg_flex_700h_firmware:5.37:-::::::* cpe:2.3:o:zyxel:usg_flex_700h_firmware:5.37:patch1::::::* OR cpe:2.3:h:zyxel:usg_flex_700h:-:::::::*
Changed	Reference Type	https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024 No Types Assigned	https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024 Vendor Advisory
Changed	Reference Type	https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024 No Types Assigned	https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024 Vendor Advisory

New CVE Received from Zyxel Corporation 2/19/2024 10:15:07 PM

Action	Type	New Value
Added	Description	A format string vulnerability in a function of the IPSec VPN feature in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1, USG FLEX series firmware versions from 4.50 through 5.37 Patch 1, USG FLEX 50(W) series firmware versions from 4.16 through 5.37 Patch 1, and USG20(W)-VPN series firmware versions from 4.16 through 5.37 Patch 1 could allow an attacker to achieve unauthorized remote code execution by sending a sequence of specially crafted payloads containing an invalid pointer; however, such an attack would require detailed knowledge of an affected device’s memory layout and configuration.
Added	CVSS V3.1	Zyxel Corporation AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Added	CWE	Zyxel Corporation CWE-134
Added	Reference	Zyxel Corporation https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024 [No types assigned]

Quick Info

CVE Dictionary Entry:
CVE-2023-6764
NVD Published Date:
02/19/2024
NVD Last Modified:
06/17/2026
Source:
Zyxel Corporation

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