CVE-2021-21571

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-06-24 · updated 2026-06-17
Weakness: CWE-295

Description

Dell UEFI BIOS https stack leveraged by the Dell BIOSConnect feature and Dell HTTPS Boot feature contains an improper certificate validation vulnerability. A remote unauthenticated attacker may exploit this vulnerability using a person-in-the-middle attack which may lead to a denial of service and payload tampering.

Affected products

Dell Alienware M15 R6 Firmware: before 1.3.3 — fixed in 1.3.3
Dell Chengming 3990 Firmware: before 1.4.1 — fixed in 1.4.1
Dell Chengming 3991 Firmware: before 1.4.1 — fixed in 1.4.1
Dell G15 5510 Firmware: before 1.4.0 — fixed in 1.4.0
Dell G15 5511 Firmware: before 1.3.3 — fixed in 1.3.3
Dell G3 3500 Firmware: before 1.9.0 — fixed in 1.9.0
Dell G5 5500 Firmware: before 1.9.0 — fixed in 1.9.0
Dell G7 7500 Firmware: before 1.9.0 — fixed in 1.9.0
Dell G7 7700 Firmware: before 1.9.0 — fixed in 1.9.0
Dell Inspiron 14 5418 Firmware: before 2.1.0_a06 — fixed in 2.1.0_a06
Dell Inspiron 15 5518 Firmware: before 2.1.0_a06 — fixed in 2.1.0_a06
Dell Inspiron 15 7510 Firmware: before 1.0.4 — fixed in 1.0.4
Dell Inspiron 3501 Firmware: before 1.6.0 — fixed in 1.6.0
Dell Inspiron 3880 Firmware: before 1.4.1 — fixed in 1.4.1
Dell Inspiron 3881 Firmware: before 1.4.1 — fixed in 1.4.1
Dell Inspiron 3891 Firmware: before 1.0.11 — fixed in 1.0.11
Dell Inspiron 5300 Firmware: before 1.7.1 — fixed in 1.7.1
Dell Inspiron 5301 Firmware: before 1.8.1 — fixed in 1.8.1
Dell Inspiron 5310 Firmware: before 2.1.0 — fixed in 2.1.0
Dell Inspiron 5400 2-In-1 Firmware: before 1.7.0 — fixed in 1.7.0
Dell Inspiron 5400 Aio Firmware: before 1.4.0 — fixed in 1.4.0
Dell Inspiron 5401 Aio Firmware: before 1.4.0 — fixed in 1.4.0
Dell Inspiron 5401 Firmware: before 1.7.2 — fixed in 1.7.2
Dell Inspiron 5402 Firmware: before 1.5.1 — fixed in 1.5.1
Dell Inspiron 5406 2N1 Firmware: before 1.5.1 — fixed in 1.5.1
Dell Inspiron 5408 Firmware: before 1.7.2 — fixed in 1.7.2
Dell Inspiron 5409 Firmware: before 1.5.1 — fixed in 1.5.1
Dell Inspiron 5410 2-In-1 Firmware: before 2.1.0 — fixed in 2.1.0
Dell Inspiron 5501 Firmware: before 1.7.2 — fixed in 1.7.2
Dell Inspiron 5502 Firmware: before 1.5.1 — fixed in 1.5.1

How to fix

Upgrade to a fixed version: Dell Alienware M15 R6 Firmware 1.3.3; Dell Chengming 3990 Firmware 1.4.1; Dell Chengming 3991 Firmware 1.4.1; Dell G15 5510 Firmware 1.4.0; Dell G15 5511 Firmware 1.3.3; Dell G3 3500 Firmware 1.9.0; Dell G5 5500 Firmware 1.9.0; Dell G7 7500 Firmware 1.9.0; Dell G7 7700 Firmware 1.9.0; Dell Inspiron 14 5418 Firmware 2.1.0_a06; Dell Inspiron 15 5518 Firmware 2.1.0_a06; Dell Inspiron 15 7510 Firmware 1.0.4. Check the vendor advisory for mitigations.

References

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