Dell UEFI BIOS https stack leveraged by the Dell BIOSConnect feature and Dell HTTPS Boot feature contains an improper certificate validatio…

published 2021-06-24 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8843

cvss: 5.9; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits: 0; none known

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.

Patch / fix

fixed in 20

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
dell inspiron_3501_firmware 1.6.0
dell inspiron_3880_firmware 1.4.1
dell inspiron_3881_firmware 1.4.1
dell inspiron_3891_firmware 1.0.11
dell inspiron_5300_firmware 1.7.1
dell inspiron_5301_firmware 1.8.1
dell inspiron_5310_firmware 2.1.0
dell inspiron_5400_2-in-1_firmware 1.7.0

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.9	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
NVD	2.0	5.8	AV:N/AC:M/Au:N/C:N/I:P/A:P

Affected products

Dell UEFI BIOS https stack

Classification

Weakness

CWE-295 Improper Certificate Validation

References

dell.com /support/kbdoc/en-us/000188682
vendor-advisory

Sources

CVE List CVE-2021-21571
NVD CVE-2021-21571

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