What’s Vulnerable › Vulnerabilities

CVE-2021-21555

• Severity: medium (CVSS 6.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-14 · updated 2026-06-17
• Weakness: CWE-122

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.

Affected products

• Dell Poweredge Mx740C Firmware: before 2.11.2 — fixed in 2.11.2
• Dell Poweredge Mx840C Firmware: before 2.11.2 — fixed in 2.11.2
• Dell Poweredge R640 Firmware: before 2.11.2 — fixed in 2.11.2
• Dell Poweredge R740 Firmware: before 2.11.2 — fixed in 2.11.2
• Dell Poweredge R740Xd Firmware: before 2.11.2 — fixed in 2.11.2
• Dell Poweredge R840 Firmware: before 2.11.2 — fixed in 2.11.2
• Dell Poweredge R940 Firmware: before 2.11.2 — fixed in 2.11.2
• Dell Poweredge R940Xa Firmware: before 2.11.2 — fixed in 2.11.2
• Dell Poweredge T640 Firmware: before 2.11.2 — fixed in 2.11.2

How to fix

Upgrade to a fixed version: Dell Poweredge Mx740C Firmware 2.11.2; Dell Poweredge Mx840C Firmware 2.11.2; Dell Poweredge R640 Firmware 2.11.2; Dell Poweredge R740 Firmware 2.11.2; Dell Poweredge R740Xd Firmware 2.11.2; Dell Poweredge R840 Firmware 2.11.2; Dell Poweredge R940 Firmware 2.11.2; Dell Poweredge R940Xa Firmware 2.11.2; Dell Poweredge T640 Firmware 2.11.2. Check the vendor advisory for mitigations.

References

• https://www.dell.com/support/kbdoc/000187958
• https://www.dell.com/support/kbdoc/000187958

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