Dell PowerEdge R640, R740, R740XD, R840, R940, R940xa, MX740c, MX840c, and T640 Server BIOS contain a heap-based buffer overflow vulnerabil…

published 2021-06-14 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8827

cvss: 6.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

Dell PowerEdge BIOS Intel 15G 2.11.2

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.1	CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:L
NVD	3.1	6.7	CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.2	AV:L/AC:L/Au:N/C:C/I:C/A:C

Affected products

Dell PowerEdge BIOS Intel 15G

Classification

Weakness

CWE-122 Heap-based Buffer Overflow
CWE-787 Out-of-bounds Write

References

dell.com /support/kbdoc/000187958
vendor-advisory

Sources

CVE List CVE-2021-21555
NVD CVE-2021-21555

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary