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Fencer Intel
medium 5.9

CVE-2021-21571 json

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

published 5y ago modified 4mo 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

Summary

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

  • 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

Is CVE-2021-21571 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-09).

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

Sources

Fencer Intel 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.