dbcve.org
Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 11 Feb 2022. Known ransomware use
Sma 200 FirmwareOperating system · Sonicwall

CVE-2021-20038

CRITICAL · 9.8 CVSS v3.1 Published 2021-12-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware High EPSS Public exploit Remotely reachable No privileges Zero-click

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 · unedited
A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module environment variables allows a remote unauthenticated attacker to potentially execute code as a 'nobody' user in the appliance. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances firmware 10.2.0.8-37sv, 10.2.1.1-19sv, 10.2.1.2-24sv 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 confidence

A stack-based buffer overflow exists in the Apache httpd mod_cgi module's handling of environment variables on affected SMA100 appliances. The vulnerability is remotely exploitable without authentication, allowing an attacker to potentially execute arbitrary code with 'nobody' user privileges. This affects SMA 200, 210, 400, 410, and 500v models running firmware versions 10.2.0.8-37sv, 10.2.1.1-19sv, 10.2.1.2-24sv and earlier.

MitigationApply the vendor-supplied firmware update to a patched version that addresses this vulnerability. If patching is not immediately feasible, consider restricting network access to the SMA management interfaces or implementing additional network segmentation controls.

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
Sma 200 FirmwareOperating system
Affected:= 10.2.0.8-37sv= 10.2.1.1-19sv= 10.2.1.2-24sv
Sma 210 FirmwareOperating system
Affected:= 10.2.0.8-37sv= 10.2.1.1-19sv= 10.2.1.2-24sv
Sma 410 FirmwareOperating system
Affected:= 10.2.0.8-37sv= 10.2.1.1-19sv= 10.2.1.2-24sv
Sma 400 FirmwareOperating system
Affected:= 10.2.0.8-37sv= 10.2.1.1-19sv= 10.2.1.2-24sv
Sma 500v FirmwareOperating system
Affected:= 10.2.0.8-37sv= 10.2.1.1-19sv= 10.2.1.2-24sv

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify SMA appliance model
    Access the SMA web interface or CLI and retrieve the hardware model information. Look for SMA 200, SMA 210, SMA 400, SMA 410, or SMA 500v designations in the system status or device information page.
    Affected if The appliance model is one of: SMA 200, SMA 210, SMA 400, SMA 410, or SMA 500v.
  2. Check installed firmware version
    Navigate to the SMA management console, typically under System > Status or Management > Firmware Management. Record the exact firmware version string displayed (e.g., 10.2.0.8-37sv).
    Affected if The firmware version exactly matches 10.2.0.8-37sv, 10.2.1.1-19sv, or 10.2.1.2-24sv.
  3. Verify CGI module exposure
    Inspect the Apache configuration on the SMA appliance for mod_cgi settings. In the CLI, check for any exposed CGI paths or scripts accessible via HTTP/HTTPS that could receive environment variables.
    Affected if CGI scripts or the mod_cgi module is accessible via the appliance's web interface without authentication restrictions.
  4. Confirm network accessibility of CGI endpoint
    Test if the SMA web interface is exposed to the network. Use a browser or curl to attempt access to common CGI paths (e.g., /cgi-bin/*) on the appliance's IP address.
    Affected if The SMA appliance HTTP/HTTPS ports are accessible from untrusted networks and CGI endpoints are reachable.

The environment is affected if the SMA appliance model is one of the five affected variants AND the installed firmware version is exactly one of the three vulnerable versions listed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor-supplied firmware update to a patched version that addresses this vulnerability. If patching is not immediately feasible, consider restricting network access to the SMA management interfaces or implementing additional network segmentation controls.

Recommended fix Moderate confidence

Firmware version 10.2.1.4-48sv or later (contact SonicWall for exact latest stable release)

  1. 1. Identify the exact SMA 100 appliance model (200, 210, 400, 410, or 500v) requiring remediation.
  2. 2. Visit the official SonicWall support portal at psirt.global.sonicwall.com to obtain the latest firmware security patch.
  3. 3. Download the patched firmware version (version 10.2.1.4-48sv or later, as this is the first version after the vulnerable 10.2.1.2-24sv release).
  4. 4. Review the firmware upgrade instructions in the SMA 100 Series administration guide.
  5. 5. Schedule a maintenance window as firmware upgrades may cause temporary service interruption.
  6. 6. Backup the current SMA configuration before performing the upgrade.
  7. 7. Upload and install the new firmware through the SMA web management interface or CLI.
  8. 8. After reboot, verify the new firmware version is installed and the appliance is functioning normally.
Caveat Firmware upgrades may cause brief service interruption and could introduce changes to configuration parameters; backup configuration before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Sma 200 Firmware Exploited in the wild — priority engagement
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-20038 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-20038 in production — separate from our analysis above.

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.

What this is

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.

What belongs here
  • 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