CVE-2021-20035: SonicWall SMA100 Appliances OS Command Injection Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 16 Apr 2025, 1,297 days after the CVE record was published.

How likely is exploitation in the next 30 days?

4.4%

EPSS score, percentile 91.3 of all scored records

How severe?

6.5 Medium

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

Required action (CISA), due 7 May 2025: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected: 9.0.0.10-28sv and earlier; 10.2.0.7-34sv and earlier; 10.2.1.0-17sv and earlier

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 7 May 2025.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

• https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0022
• https://nvd.nist.gov/vuln/detail/CVE-2021-20035

Affected products and versions

As listed in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

SonicWall SMA100 appliances contain an OS command injection vulnerability in the management interface that allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user, which could potentially lead to code execution.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2021-20035 to its Known Exploited Vulnerabilities (KEV) catalog on 16 Apr 2025.
• CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
• The due date CISA sets for the required action is 7 May 2025.
• The CVE record was published on 27 Sep 2021, 1,297 days before it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 6.5 (Medium), taken from CISA's enrichment of the record.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 4.4% (percentile 91.3), as of 28 Oct 2026.
• CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

References

• psirt.global.sonicwall.com

More exploited SonicWall vulnerabilities

• CVE-2026-83548: SonicWall SMA1000 Appliances Server-Side Request Forgery Vulnerability (added 2 Sep 2026)
• CVE-2026-83549: SonicWall SMA1000 Appliances OS Command Injection Vulnerability (added 2 Sep 2026)
• CVE-2026-15409: SonicWall SMA1000 Appliances Server-Side Request Forgery Vulnerability (added 14 Jul 2026)
• CVE-2026-15410: SonicWall SMA1000 Appliances Code Injection Vulnerability (added 14 Jul 2026)
• CVE-2025-40602: SonicWall SMA1000 Missing Authorization Vulnerability (added 17 Dec 2025)
• CVE-2023-44221: SonicWall SMA100 Appliances OS Command Injection Vulnerability (added 1 May 2025)