Vulnerability report

Active exploitation observed Confirmed confidence In CISA KEV

CVE-2021-20016

SonicWall SMA100

SonicWall SMA100 · SMA100 build version 10.x

Watch CVE-2021-20016 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
40.0%
First observed
27 Jun 2026
Last observed
04 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-20016 is an unauthenticated vulnerability affecting SonicWall SMA100. A SQL-Injection vulnerability in the SonicWall SSLVPN SMA100 product allows a remote unauthenticated attacker to perform SQL query to...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

SonicWall SMA100 sma100 build version 10.x.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

SonicWall SMA100

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.

SonicWall Affected
SonicWall SMA100
SMA100 build version 10.x
Published
03 Feb 2021
Exploitation Reported
03 Nov 2021
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

cisa malware ransomware edge

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 03 Nov 2021

A trusted third party reported exploitation.

Active exploitation observed

Previdian sensor

First observed 27 Jun 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Used in malware

CISA

Recorded 03 Nov 2021

Malware families have been linked to exploitation of this CVE.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2021-11-03 00:00 UTC
Tenable Blog 2026-07-15 17:14 UTC
Previdian Sensors 2026-07-23 11:02 UTC
CVE 2026-08-12 04:21 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

19

Attempts observed

13

Unique attacker IPs

11

Attacker countries

BG · CH · DE · FI · FR · GB · JP · NL · SC · US · YE

13

Sensors observed

CVE-2021-20016 exploitation attempts over the last 84 days

Daily events observed by Previdian sensors

Updated 09 Oct 2026

0
2
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
0
2
2
1
1
0
3
0
0
0
0
0
18 Jul 4 Aug 21 Aug 7 Sep 9 Oct

First observed 27 Jun 2026 · Last observed 04 Oct 2026

Pro adds sensor region and window summaries. Enterprise adds raw IPs, paths, User-Agents, and payloads.

Start 14-day Pro trial

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
1
1
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

Previdian virtual patch guidance is available for this CVE.

AWS WAF Cloudflare ModSecurity

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Virtual Patch Detail

Compensating WAF rules for this CVE.

Available

Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to Previdian Enterprise users.

Talk to Sales Learn About Virtual Patches

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

40.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') CWE-89

Recent mention · Tenable Blog

CVE-2026-15409, CVE-2026-15410: SonicWall SMA 1000 zero-day vulnerabilities exploited in the wild

SonicWall patched two recently exploited zero-day vulnerabilities in its SMA 1000 Series secure remote access appliances which may have been chained for unauthenticated remote code execution.Key takeawaysCVE-2026-15409 and CVE-2026-15410 are a pair of exploited vulnerabilities...

Read full advisory

All CVSS Scores

CVSS v3.1 9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 7.5 High

AV:N/AC:L/Au:N/C:P/I:P/A:P

Timeline

From disclosure to observed exploitation

  1. 13:00 UTC

    Virtual patch available

    Compensating WAF rule available to block exploitation

  2. 04:21 UTC

    KEV confirmed by CVE

    Exploitation attested by an external source

  3. 17:14 UTC

    KEV confirmed by Tenable Blog

    Exploitation attested by an external source

  4. 09:38 UTC

    Indicators of compromise added (32)

    Indicators of compromise recorded

  5. 09:38 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  6. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  7. 00:00 UTC

    First public exploitation report

    Exploit observed in malware

  8. 20:35 UTC

    CVE published

    Vulnerability disclosed publicly

  9. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-20016

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-20016",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.40038,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 19, "sensors": 13 }
}