CVE & CISA-KEV Catalog

CVE-2021-21556

MEDIUM
6.1
CVSS v3
NVD

Description

Dell PowerEdge R640, R740, R740XD, R840, R940, R940xa, MX740c, MX840c, and T640 Server BIOS contain a stack-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.

CWE-121Stack-based Buffer OverflowCWE-787Out-of-bounds Write

How to fix

Remediation Available
poweredge mx740c firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD
poweredge mx840c firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD
poweredge r640 firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD
poweredge r740 firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD
poweredge r740xd firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD
poweredge r840 firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD
poweredge r940 firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD
poweredge r940xa firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD
poweredge t640 firmwareNVD
Affected:< 2.11.2Fixed in:2.11.2CVE-2021-21556derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal
Attack ComplexityLow
Privileges RequiredHigh
User InteractionRequired
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityLow

CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:L

Exploit Intelligence

0.31%probability of exploitation in 30 days
22ndpercentile

Low risk: more likely to be exploited than 22% of all known CVEs.

References

Vendor Advisory1

Related Vulnerabilities

Other CWE-121 (Stack-based Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2025-22457Critical9.0100%KEV + RansomFix
CVE-2025-0282Critical9.0100%KEV + Ransom-
CVE-2021-20038Critical9.8100%KEV + Ransom-
CVE-2009-0927High8.897%KEVFix
CVE-2020-10924High8.887%--
CVE-2022-20705Critical10.080%--
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CVE-2021-21556 severity badge

Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.