{"id":"CVE-2021-21555","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-21555","generatedAt":"2026-10-27T22:28:23.625Z","title":"Dell PowerEdge R640, R740, R740XD, R840, R940, R940xa, MX740c, MX840c, and T640 Server BIOS contain a heap-based buffer overflow vulnerability in systems with NVDIMM-N installed.","description":"Dell PowerEdge R640, R740, R740XD, R840, R940, R940xa, MX740c, MX840c, and T640 Server BIOS contain a heap-based buffer overflow vulnerability in systems with NVDIMM-N installed. A local malicious user with high privileges may potentially exploit this vulnerability, leading to a denial of Service, arbitrary code execution, or information disclosure in UEFI or BIOS Preboot Environment.","published":"2021-06-14T19:15:08.000Z","lastModified":"2026-06-17T03:35:46.000Z","status":"Modified","sourceIdentifier":"security_alert@emc.com","cvss":{"version":"3.1","score":6.7,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-122","CWE-787"],"affected":["dell/poweredge r640 firmware","dell/poweredge r740 firmware","dell/poweredge r740xd firmware","dell/poweredge r940 firmware","dell/poweredge r840 firmware","dell/poweredge r940xa firmware","dell/poweredge t640 firmware","dell/poweredge mx740c firmware","dell/poweredge mx840c firmware"],"epss":{"score":0.00314,"percentile":0.24068,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://www.dell.com/support/kbdoc/000187958","tags":["Vendor Advisory"],"source":"security_alert@emc.com"},{"url":"https://www.dell.com/support/kbdoc/000187958","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-21555","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."}