What is the CVSS score of CVE-2023-33010?

CVE-2023-33010 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 28.8%.

Is CVE-2023-33010 being actively exploited?

Yes, CVE-2023-33010 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild exploitation. Immediate patching is required.

Usg 40 Firmware CVE-2023-33010

CRITICAL

Classic Buffer Overflow (CWE-120)

2023-05-24 security@zyxel.com.tw

RCE Buffer Overflow Zyxel Usg 40 Firmware Usg 40W Firmware Usg 60 Firmware Usg 60W Firmware Usg 20W Vpn Firmware Atp200 Firmware Atp500 Firmware Atp800 Firmware Usg20 Vpn Firmware Vpn50 Firmware Vpn100 Firmware Vpn300 Firmware Atp100 Firmware Vpn1000 Firmware Atp100W Firmware Atp700 Firmware Usg Flex 100 Firmware Usg Flex 100W Firmware Usg Flex 200 Firmware Usg Flex 500 Firmware Usg Flex 700 Firmware Usg Flex 50W Firmware Usg Flex 50 Firmware

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Added to CISA KEV

Jul 14, 2026 - 04:22 CISA

CVE Published

May 24, 2023 - 13:15 nvd

CRITICAL 9.8

DescriptionNVD

A buffer overflow vulnerability in the ID processing function in Zyxel ATP series firmware versions 4.32 through 5.36 Patch 1, USG FLEX series firmware versions 4.50 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.25 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.25 through 5.36 Patch 1, VPN series firmware versions 4.30 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.25 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.

AnalysisAI

A buffer overflow vulnerability in the ID processing function in Zyxel ATP series firmware versions 4.32 through 5.36 Patch 1, USG FLEX series firmware versions 4.50 through 5.36 Patch 1, USG FLEX. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Technical ContextAI

This vulnerability is classified as Buffer Copy without Size Check (CWE-120), which allows attackers to overflow a buffer to corrupt adjacent memory. A buffer overflow vulnerability in the ID processing function in Zyxel ATP series firmware versions 4.32 through 5.36 Patch 1, USG FLEX series firmware versions 4.50 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.25 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.25 through 5.36 Patch 1, VPN series firmware versions 4.30 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.25 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device. Affected products include: Zyxel Atp100 Firmware, Zyxel Atp200 Firmware, Zyxel Atp500 Firmware, Zyxel Atp100W Firmware, Zyxel Atp700 Firmware. Version information: through 5.36.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Always validate buffer sizes before copy operations. Use bounded functions (strncpy, snprintf). Enable compiler protections.