CVE-2021-21557

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-20

Description

Dell PowerEdge Server BIOS and select Dell Precision Rack BIOS contain an out-of-bounds array access vulnerability. 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 System Management Mode.

Affected products

Dell Poweredge C4140 Firmware: before 2.11.2 — fixed in 2.11.2
Dell Poweredge C6420 Firmware: before 2.11.2 — fixed in 2.11.2
Dell Poweredge C6525 Firmware: before 2.2.4 — fixed in 2.2.4
Dell Poweredge Fc640 Firmware: before 2.11.2 — fixed in 2.11.2
Dell Poweredge M640 Firmware: before 2.11.2 — fixed in 2.11.2
Dell Poweredge M640P Firmware: before 2.11.2 — fixed in 2.11.2
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 R240 Firmware: before 2.5.1 — fixed in 2.5.1
Dell Poweredge R340 Firmware: before 2.5.1 — fixed in 2.5.1
Dell Poweredge R440 Firmware: before 2.11.2 — fixed in 2.11.2
Dell Poweredge R540 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 R6415 Firmware: before 1.16.1 — fixed in 1.16.1
Dell Poweredge R6515 Firmware: before 2.2.4 — fixed in 2.2.4
Dell Poweredge R6525 Firmware: before 2.2.5 — fixed in 2.2.5
Dell Poweredge R740 Firmware: before 2.11.2 — fixed in 2.11.2
Dell Poweredge R740Xd2 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 R7415 Firmware: before 1.16.1 — fixed in 1.16.1
Dell Poweredge R7425 Firmware: before 1.16.1 — fixed in 1.16.1
Dell Poweredge R7515 Firmware: before 2.2.4 — fixed in 2.2.4
Dell Poweredge R7525 Firmware: before 2.2.5 — fixed in 2.2.5
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 T140 Firmware: before 2.5.1 — fixed in 2.5.1
Dell Poweredge T340 Firmware: before 2.5.1 — fixed in 2.5.1
Dell Poweredge T440 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 C4140 Firmware 2.11.2; Dell Poweredge C6420 Firmware 2.11.2; Dell Poweredge C6525 Firmware 2.2.4; Dell Poweredge Fc640 Firmware 2.11.2; Dell Poweredge M640 Firmware 2.11.2; Dell Poweredge M640P Firmware 2.11.2; Dell Poweredge Mx740C Firmware 2.11.2; Dell Poweredge Mx840C Firmware 2.11.2; Dell Poweredge R240 Firmware 2.5.1; Dell Poweredge R340 Firmware 2.5.1; Dell Poweredge R440 Firmware 2.11.2; Dell Poweredge R540 Firmware 2.11.2. Check the vendor advisory for mitigations.

References

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