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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Nov 2021. Known ransomware use
Sma 100 FirmwareOperating system · Sonicwall

CVE-2021-20016

CRITICAL · 9.8 CVSS v3.1 Published 2021-02-04
Fix available
A fix is available. Upgrade to 10.2.0.5-d-29sv or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware 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 SQL-Injection vulnerability in the SonicWall SSLVPN SMA100 product allows a remote unauthenticated attacker to perform SQL query to access username password and other session related information. This vulnerability impacts SMA100 build version 10.x.

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 confidence

A SQL injection vulnerability in SonicWall SSLVPN SMA100 allows remote unauthenticated attackers to execute arbitrary SQL queries, enabling extraction of usernames, passwords, and session information. The flaw exists in version 10.x builds and is exploitable over the network without credentials.

MitigationApply vendor-supplied patches or upgrades to the SMA100 firmware; as an interim control, restrict VPN management interface exposure to trusted networks only.

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 100 FirmwareOperating system
Affected:>= 10.0.0.0, < 10.2.0.5-d-29sv
Sma 200 FirmwareOperating system
Affected:all versions
Sma 210 FirmwareOperating system
Affected:all versions
Sma 400 FirmwareOperating system
Affected:all versions
Sma 410 FirmwareOperating system
Affected:all versions
Sma 500vApplication
Affected:all versions

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 the SMA device model
    Access the SMA management web interface and navigate to System > Status or check the device label to determine if the device is an SMA 100, 200, 210, 400, 410, or 500v model
    Affected if Device is any SMA 200, 210, 400, 410, or 500v (all versions affected); or SMA 100 series running 10.x firmware
  2. Check the installed firmware version
    In the SMA web interface, go to System > Status or Maintenance > Firmware Management to view the current firmware version. For CLI access, log in and run 'fwver' or 'version' command
    Affected if SMA 100 firmware is 10.0.0.0 or higher but lower than 10.2.0.5-d-29sv; all firmware versions of SMA 200/210/400/410/500v are affected
  3. Verify SSLVPN service is enabled
    In the SMA web interface, navigate to Users > SSL-VPN or VPN > SSL-VPN Settings to confirm whether the SSLVPN feature is currently enabled
    Affected if SSLVPN is enabled and the device model/version falls within the affected ranges - the SQL injection targets this specific component
  4. Review access logs for unauthorized SQL queries
    Check System > Logs or Log > View Logs for entries containing SQL syntax, UNION SELECT statements, or unexpected database errors around the SSLVPN authentication endpoints
    Affected if Suspicious SQL injection patterns appear in logs, indicating possible exploitation attempts

The environment is affected if the device is an SMA 200/210/400/410/500v at any firmware version, or an SMA 100 series running firmware 10.0.0.0 through 10.2.0.5-d-29sv, and the SSLVPN feature is enabled.

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
Upgrade available Upgrade to 10.2.0.5-d-29sv or later
Fixed in 10.2.0.5-d-29sv
Interim mitigation

Apply vendor-supplied patches or upgrades to the SMA100 firmware; as an interim control, restrict VPN management interface exposure to trusted networks only.

Recommended fix High confidence

SMA 100 series: upgrade to firmware version 10.2.0.5-d-29sv or later (10.2.0.x branch); SMA 200/210/400/410/500v: contact vendor for specific fix

  1. 1. Identify the current firmware version of the affected SonicWall SMA device by accessing the web management interface or running 'get system status' via CLI
  2. 2. For SMA 100 series devices: Schedule a maintenance window and back up the current device configuration
  3. 3. Download the fixed firmware version 10.2.0.5-d-29sv or later from the official SonicWall support portal (mysonicwall.com)
  4. 4. Upload the firmware through the web interface under Administration > Firmware Management or via CLI using 'firmware upgrade' command
  5. 5. After upgrade, verify the device is operational and confirm the new version matches the fixed release
  6. 6. For SMA 200, 210, 400, 410, and 500v: Contact SonicWall support to confirm available patch or migration path, as these older models may require firmware updates or replacement
Caveat Review release notes for 10.2.0.x for any configuration or feature changes; some legacy features may be deprecated

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

Fix this in Sma 100 Firmware Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2021-20016 in production — separate from our analysis above.

No notes yet

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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