CVE-2021-20026
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 NSM On-Prem product allows an authenticated attacker to perform OS command injection using a crafted HTTP request. This vulnerability affects NSM On-Prem 2.2.0-R10 and earlier versions.
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 confidenceOS command injection vulnerability in SonicWall NSM On-Prem allows authenticated attackers to execute arbitrary operating system commands by sending crafted HTTP requests. This occurs due to insufficient input validation in the web interface.
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< 2.2.0= 2.2.0CVSS 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
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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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Identify the installed NSM On-Prem versionLog into the SonicWall NSM On-Prem web interface and navigate to the About or System Information page to view the current software version. Alternatively, check the version from the NSM server's command line interface if you have direct access.Affected if The installed version is 2.2.0 or any version lower than 2.2.0-R10 (including all 2.2.0 versions). Compare your version against the affected range: versions < 2.2.0 and version = 2.2.0 are vulnerable.
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Verify if the NSM web management interface is network-accessibleDetermine if the NSM On-Prem management interface (typically ports 443 or 8443) is exposed to untrusted networks by reviewing firewall rules, NAT configurations, or performing a port scan from an external IP address.Affected if The management interface is accessible from untrusted networks or the internet, increasing the risk that compromised credentials could be exploited remotely.
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Review authenticated user accountsAccess the NSM On-Prem administration panel and list all user accounts with access to the management interface. Identify any accounts that may have weak or default credentials.Affected if Any authenticated user account exists in the system, as the vulnerability allows any authenticated attacker to execute commands.
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Check for suspicious command execution indicatorsReview NSM server logs and audit trails for unusual or unexpected command execution entries, especially HTTP requests containing shell metacharacters or unusual parameters in web server access logs.Affected if Logs show unexpected commands, unusual HTTP request patterns, or evidence of unauthorized command execution originating from the NSM web interface.
You are affected if your installed SonicWall Network Security Manager On-Prem version is 2.2.0 or any version lower than 2.2.0-R10, and the management interface is accessible to authenticated users (including untrusted networks).
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 · scoped2.2.0
Upgrade NSM On-Prem to a version newer than 2.2.0-R10. Until patched, restrict network access to the management interface to trusted IPs only and minimize the number of authenticated users.
NSM On-Prem version > 2.2.0 (e.g., 2.3.0 or later stable release)
- 1. Back up the current NSM On-Prem configuration and database according to SonicWall backup procedures.
- 2. Download the latest NSM On-Prem release from the official SonicWall support portal (psirt.global.sonicwall.com or sonicwall.com/support).
- 3. Verify the downloaded image integrity using SHA256 checksums provided by SonicWall.
- 4. Follow the official SonicWall NSM On-Prem upgrade documentation to install the updated version.
- 5. After upgrade, verify the NSM On-Prem services are running correctly.
- 6. Test that the previously vulnerable functionality is now inaccessible to authenticated users without proper command filtering.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20026 — 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-2021-20026 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