{"id":"CVE-2021-21727","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-21727","generatedAt":"2026-10-28T06:36:04.479Z","title":"A ZTE product has a DoS vulnerability.","description":"A ZTE product has a DoS vulnerability. A remote attacker can amplify traffic by sending carefully constructed IPv6 packets to the affected devices, which eventually leads to device denial of service. This affects:<ZXHN F623><All versions up to V6.0.0P3T33>","published":"2021-03-29T16:15:13.000Z","lastModified":"2026-06-17T03:36:03.000Z","status":"Modified","sourceIdentifier":"psirt@zte.com.cn","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["zte/zxhn f623 firmware"],"epss":{"score":0.01437,"percentile":0.72998,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (1.44%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1014744","tags":["Vendor Advisory"],"source":"psirt@zte.com.cn"},{"url":"https://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1014744","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-21727","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}