{"cve":"CVE-2021-0240","nvd":{"published":"2021-04-22T20:15:08.977","modified":"2026-06-17T03:29:34.637","status":"Modified","description":"On Juniper Networks Junos OS platforms configured as DHCPv6 local server or DHCPv6 Relay Agent, the Juniper Networks Dynamic Host Configuration Protocol Daemon (JDHCPD) process might crash if a malformed DHCPv6 packet is received, resulting in a restart of the daemon. The daemon automatically restarts without intervention, but continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue only affects DHCPv6. DHCPv4 is not affected by this issue. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S12; 17.4 versions prior to 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R1-S8, 18.4R3-S7; 19.1 versions prior to 19.1R3-S5; 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R3-S2; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R2.","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-755","CWE-703"],"references":["https://kb.juniper.net/JSA11168","https://kb.juniper.net/JSA11168"],"products":["juniper:junos"],"source":"nvd","synced_at":"2026-10-19T21:17:01.373894544+00:00"},"epss":{"cve":"CVE-2021-0240","score":0.00397,"percentile":0.33986,"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."]}