What is the CVSS score of CVE-2023-34140?

CVE-2023-34140 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.3%.

Usg 20W Vpn Firmware CVE-2023-34140

MEDIUM

Classic Buffer Overflow (CWE-120)

2023-07-17 security@zyxel.com.tw

Buffer Overflow Denial Of Service Zyxel Usg 20W Vpn Firmware Usg 2200 Vpn Firmware Usg Flex 100 Firmware Usg Flex 100W Firmware Usg Flex 200 Firmware Usg Flex 50 Firmware Usg Flex 500 Firmware Usg Flex 50W Firmware Usg Flex 700 Firmware Zywall Atp100 Firmware Zywall Atp100W Firmware Zywall Atp200 Firmware Zywall Atp500 Firmware Zywall Atp700 Firmware Zywall Atp800 Firmware Zywall Vpn100 Firmware Zywall Vpn2S Firmware Zywall Vpn300 Firmware Zywall Vpn50 Firmware Zywall Vpn 100 Firmware Zywall Vpn 300 Firmware Zywall Vpn 50 Firmware Nxc2500 Firmware Nxc5500 Firmware

6.5

CVSS 3.1 · Vendor: zyxel

Severity by source

Vendor (zyxel) PRIMARY

6.5 MEDIUM

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

Primary rating from Vendor (zyxel) · only source for this CVE.

CVSS VectorVendor: zyxel

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

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

CVE Published

Jul 17, 2023 - 18:15 cve.org

MEDIUM 6.5

DescriptionCVE.org

A buffer overflow vulnerability in the Zyxel ATP series firmware versions 4.32 through 5.36 Patch 2, USG FLEX series firmware versions 4.50 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 4.16 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 4.16 through 5.36 Patch 2, VPN series firmware versions 4.30 through 5.36 Patch 2, NXC2500 firmware versions 6.10(AAIG.0) through 6.10(AAIG.3), and NXC5500 firmware versions 6.10(AAOS.0) through 6.10(AAOS.4), could allow an unauthenticated, LAN-based attacker to cause denial of service (DoS) conditions by sending a crafted request to the CAPWAP daemon.

AnalysisAI

A buffer overflow vulnerability in the Zyxel ATP series firmware versions 4.32 through 5.36 Patch 2, USG FLEX series firmware versions 4.50 through 5.36 Patch 2, USG FLEX 50(W) series firmware. Rated medium severity (CVSS 6.5), this vulnerability is 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 Zyxel ATP series firmware versions 4.32 through 5.36 Patch 2, USG FLEX series firmware versions 4.50 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 4.16 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 4.16 through 5.36 Patch 2, VPN series firmware versions 4.30 through 5.36 Patch 2, NXC2500 firmware versions 6.10(AAIG.0) through 6.10(AAIG.3), and NXC5500 firmware versions 6.10(AAOS.0) through 6.10(AAOS.4), could allow an unauthenticated, LAN-based attacker to cause denial of service (DoS) conditions by sending a crafted request to the CAPWAP daemon. Affected products include: Zyxel Usg 20W-Vpn Firmware, Zyxel Usg 2200-Vpn Firmware, Zyxel Usg Flex 100 Firmware, Zyxel Usg Flex 100W Firmware, Zyxel Usg Flex 200 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.