CVE-2021-21571
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedDell 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceDell UEFI BIOS HTTPS stack used by BIOSConnect and HTTPS Boot features contains improper certificate validation. A remote unauthenticated attacker can exploit this via a person-in-the-middle (MITM) attack, potentially causing denial of service and tampering with BIOS payloads.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.3.3< 1.4.1< 1.4.1< 1.4.0< 1.3.3< 1.9.0< 1.9.0< 1.9.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify your Dell system modelCheck system model via BIOS setup, system information, or Dell SupportAssist. Match against affected products: Alienware M15 R6, Chengming 3990, Chengming 3991, G15 5510, G15 5511, G3 3500, G5 5500, or G7 7500.Affected if System model matches one of the affected products listed in the CVE.
-
Check current BIOS firmware versionAccess BIOS setup (F2 on boot) or use Dell tools to view BIOS version. Compare against the fixed version for your model: M15 R6 needs 1.3.3, Chengming models need 1.4.1, G15 5510 needs 1.4.0, G15 5511 needs 1.3.3, G3/G5/G7 need 1.9.0.Affected if Installed firmware version is lower than the fixed version for your specific model.
-
Determine if BIOSConnect is enabledCheck BIOS setup under Advanced or Boot options for BIOSConnect feature setting. This feature may appear as part of Dell SupportAssist or BIOS recovery options.Affected if BIOSConnect is enabled and the firmware version is below the fixed version.
-
Determine if HTTPS Boot is enabledCheck BIOS setup under Boot options for HTTPS Boot or Secure Boot settings. This feature enables network boot via HTTPS.Affected if HTTPS Boot is enabled and the firmware version is below the fixed version.
You are affected if you have a Dell system from the affected product list with a firmware version lower than the fixed version AND either BIOSConnect or HTTPS Boot is enabled.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data1.3.31.4.01.4.1
Apply Dell BIOS/firmware updates addressing this vulnerability. Until patched, avoid using BIOSConnect and HTTPS Boot features on untrusted networks.
- Consultation4.0 h
- Implementation6.0 h
- Testing2.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,064.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21571 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-21571 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data