CVE-2021-20039
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 · uneditedImproper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.
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 analysisUser input reaches a shell or system command without being fully separated from the command itself, so an attacker can append their own instructions. Because these run with the application's privileges, it often means full control of the host. The lasting fix is to avoid the shell entirely — call APIs directly and pass arguments as data, never as concatenated strings.
General guidance for the os command injection class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
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= 9.0.0.11-31sv= 10.2.0.8-37sv= 10.2.1.1-19sv= 9.0.0.11-31sv= 10.2.0.8-37sv= 10.2.1.1-19sv= 9.0.0.11-31sv= 10.2.0.8-37sv= 10.2.1.1-19sv= 9.0.0.11-31sv= 10.2.0.8-37sv= 10.2.1.1-19sv= 9.0.0.11-31sv= 10.2.0.8-37sv= 10.2.1.1-19svCVSS 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
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 · scopedSonicWall SMA 100 series firmware version 10.2.1.2 or later (verify latest available version on support.sonicwall.com)
- 1. Identify the exact SMA model (200, 210, 400, 410, or 500v) currently deployed
- 2. Determine the current firmware version from the SMA management interface under System > Status
- 3. Navigate to the official SonicWall support portal (support.sonicwall.com) or the SMA product page
- 4. Locate the firmware download section for the specific SMA model
- 5. Download the latest available firmware version that supersedes the affected versions (10.2.1.1-19sv and later)
- 6. Backup the current SMA configuration from the management interface under Settings > Import/Export > Export
- 7. Access the Administration > Firmware Update section in the SMA management console
- 8. Upload and apply the new firmware version
Generated from the published advisory — verify against the referenced sources before acting.
There is no version to upgrade to and no patch to apply. Every affected install stays exposed until the vendor ships a fix — or somebody else builds one.
Free. We build fixes in the order the community asks for them — and we’ll tell you the moment this one lands.
We develop and verify an original fix where the vendor hasn’t, from $3,200. Deployed to your staging first — never straight to production.
Scope it with usSee what else the community needs solved on the solutions-needed board.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20039 — 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-2021-20039 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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- Version or environment caveats, and links to real fixes
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