Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-20035

SMA100 Denial of Service

SonicWall / SMA100 · 9.0.0.10-28sv and earlier

Watch CVE-2021-20035 Browse KEV feed
Severity
CVSS 6.5 · Medium
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
4.2%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-20035 is a vulnerability affecting SonicWall SMA100. Improper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary commands as a...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV.

Who is affected?

SonicWall / SMA100 9.0.0.10-28sv and earlier.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

SMA100 Denial of Service

Improper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user which potentially leads to DoS.

SonicWall Affected
SMA100
9.0.0.10-28sv and earlier 10.2.0.7-34sv and earlier 10.2.1.0-17sv and earlier
Published
27 Sep 2021
Exploitation Reported
16 Apr 2025
Attack vector
Remote
Complexity
Low
Privileges
Low
User interaction
None

Tags

nessus_scanner edge cisa

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 16 Apr 2025

A trusted third party reported exploitation.

Known exploited vulnerability sources

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

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Source Added
CISA First 2025-04-16 00:00 UTC

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
0
0
0

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

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nessus https://www.tenable.com/plugins/nessus/235817 02 Jun 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

6.5 Medium

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

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

EPSS

4.2%

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 OS Command ('OS Command Injection') CWE-78

All CVSS Scores

CVSS v3.1 6.5 Medium

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

CVSS v2.0 6.8 Medium

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

Timeline

From disclosure to observed exploitation

  1. 09:25 UTC

    Nessus plugin available

    Scanner coverage available

  2. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. 17:20 UTC

    CVE published

    Vulnerability disclosed publicly

  4. 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.

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  • 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-2021-20035

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-20035",
  "confidence": "Confirmed",
  "cvss_score": 6.5,
  "cvss_estimated": false,
  "epss_score": 0.04181,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}