CVE-2023-34140
6.5 · MEDIUMOverview
CVE-2023-34140 is a medium-severity vulnerability affecting zyxel usg_20w-vpn_firmware. It was published on July 17, 2023 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical Description
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.
Remediation
Check the references section for vendor advisories and patches from zyxel. Update usg_20w-vpn_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| zyxel | usg_20w-vpn_firmware | >= 4.16, < 5.37 | Affected |
| zyxel | usg_2200-vpn_firmware | >= 4.30, < 5.37 | Affected |
| zyxel | usg_flex_100_firmware | >= 4.50, < 5.37 | Affected |
| zyxel | usg_flex_100w_firmware | >= 4.50, < 5.37 | Affected |
| zyxel | usg_flex_200_firmware | >= 4.50, < 5.37 | Affected |
| zyxel | usg_flex_50_firmware | >= 4.50, < 5.37 | Affected |
| zyxel | usg_flex_500_firmware | >= 4.50, < 5.37 | Affected |
| zyxel | usg_flex_50w_firmware | >= 4.50, < 5.37 | Affected |
| zyxel | usg_flex_700_firmware | >= 4.50, < 5.37 | Affected |
| zyxel | zywall_atp100_firmware | >= 4.32, < 5.37 | Affected |
Frequently Asked Questions
What is CVE-2023-34140?
CVE-2023-34140 is a medium-severity vulnerability affecting zyxel usg_20w-vpn_firmware. It was published on July 17, 2023 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
How severe is CVE-2023-34140?
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2023-34140?
Check the references section for vendor advisories and patches from zyxel. Update usg_20w-vpn_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2023-34140?
CyberStrike's AI-powered security agents can automatically detect CVE-2023-34140 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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