{"cve":"CVE-2023-34140","nvd":{"published":"2023-07-17T18:15:09.667","modified":"2026-06-17T06:02:58.960","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-120"],"references":["https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-wlan-controllers","https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-wlan-controllers"],"products":["zyxel:nxc2500_firmware","zyxel:nxc5500_firmware","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","zyxel:usg_flex_500_firmware","zyxel:usg_flex_50_firmware","zyxel:usg_flex_50w_firmware","zyxel:usg_flex_700_firmware","zyxel:zywall_atp100_firmware","zyxel:zywall_atp100w_firmware","zyxel:zywall_atp200_firmware","zyxel:zywall_atp500_firmware","zyxel:zywall_atp700_firmware","zyxel:zywall_atp800_firmware","zyxel:zywall_vpn100_firmware","zyxel:zywall_vpn2s_firmware","zyxel:zywall_vpn300_firmware","zyxel:zywall_vpn50_firmware","zyxel:zywall_vpn_100_firmware","zyxel:zywall_vpn_300_firmware","zyxel:zywall_vpn_50_firmware"],"source":"nvd","synced_at":"2026-10-19T21:38:35.729974749+00:00"},"epss":{"cve":"CVE-2023-34140","score":0.003,"percentile":0.22797,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}