CVE-2021-20021
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 · uneditedA vulnerability in the SonicWall Email Security version 10.0.9.x allows an attacker to create an administrative account by sending a crafted HTTP request to the remote host.
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 · high confidenceA critical authentication bypass vulnerability in SonicWall Email Security versions 10.0.9.x allows unauthenticated remote attackers to create administrative user accounts by sending specially crafted HTTP requests to the application. This grants attackers full administrative access to the email security appliance.
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< 10.0.9.6103< 10.0.9.6105< 10.0.9.6105< 10.0.9.6105< 10.0.9.6105< 10.0.9.6105< 10.0.9.6105< 10.0.9.6105CVSS 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
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
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Locate the installed SonicWall Email Security versionAccess the product admin interface and navigate to the About or System Information page, or run the command 'Version' in the CLI if available, to retrieve the exact firmware/software version numberAffected if The displayed version is below 10.0.9.6103 for the base product or below 10.0.9.6105 for appliance models (9000, 3300, 4300, 8300, 5000, 7000, 5050)
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Identify the appliance modelCheck the product label, admin interface system information, or CLI output to confirm whether the deployment uses the base software or one of the listed appliance firmware versionsAffected if The appliance model matches any of the listed firmware versions and the version is below 10.0.9.6105
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Verify management interface exposureDetermine if the SonicWall Email Security web management interface (port 443 or 80) is accessible from untrusted network segments or the public internet by reviewing firewall rules, NAT configurations, or access control listsAffected if The management interface is reachable from untrusted networks without VPN or IP restriction, enabling the unauthenticated HTTP attack vector
You are affected if your installed SonicWall Email Security version is below 10.0.9.6103 (or below 10.0.9.6105 for appliance models) AND the management interface is accessible from untrusted networks, allowing the auth bypass to create unauthorized admin accounts.
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.
dbcve · scoped10.0.9.610310.0.9.6105
Immediately upgrade to a patched SonicWall Email Security version beyond 10.0.9.x. If immediate patching is not feasible, restrict network access to the management interface via firewall rules or VPN to limit exposure to untrusted networks.
Email Security: 10.0.9.6103 or later | Email Security Appliance Firmware: 10.0.9.6105 or later
- Identify the specific SonicWall product in use (Email Security software or Email Security Appliance firmware)
- For Email Security software: Download and install version 10.0.9.6103 or later from the SonicWall support portal
- For Email Security Appliance (3300, 4300, 5000, 7000, 8300, 9000, 5050): Download and apply firmware version 10.0.9.6105 or later
- After upgrading, verify the new administrative accounts were not created by reviewing the admin user list in the management interface
- If unauthorized admin accounts exist, remove them immediately and reset all administrative passwords
- Consult SonicWall release notes for any additional post-upgrade configuration requirements
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20021 — 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-2021-20021 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
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- 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