Cyber Resilience

CVE-2021-20039

RCE in Sonicwall Sma 200 Firmware 10.2.0.8-37sv … 9.0.0.11-31sv

Public PoCHigh EPSSRCECommand Injection
Published
08 December 2021
Modified
05 September 2025
Patch / advisory
View advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.78 99.5th percentile
Risk Priority 87 floored blend · peak EPSS

Summary

CVE-2021-20039 is a high-severity OS Command Injection (CWE-78) vulnerability in Sonicwall Sma 200 Firmware. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 0.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

CWE(s)
CWE-78

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1059.004 Unix Shell Executionconfidence: HIGH
CWE-78 OS command injection in the management interface directly enables execution of arbitrary Unix shell commands.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalationconfidence: HIGH
Remote authenticated command injection as 'nobody' allows the attacker to escalate privileges by exploiting the injected commands.
attack.mitre.org →
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2023-44221Same product: Sonicwall Sma 200
CVE-2021-20035Same product: Sonicwall Sma 200
CVE-2025-32821Same product: Sonicwall Sma 200
CVE-2024-40763Same product: Sonicwall Sma 200
CVE-2024-53702Same product: Sonicwall Sma 200
CVE-2021-20038Same product: Sonicwall Sma 200
CVE-2024-22395Same product: Sonicwall Sma 200
CVE-2024-45318Same product: Sonicwall Sma 200
CVE-2024-45319Same product: Sonicwall Sma 200
CVE-2023-5970Same product: Sonicwall Sma 200

Affected Assets

sonicwall
sma 200 firmware
10.2.0.8-37sv, 10.2.1.1-19sv, 9.0.0.11-31sv
sonicwall
sma 210 firmware
10.2.0.8-37sv, 10.2.1.1-19sv, 9.0.0.11-31sv
sonicwall
sma 410 firmware
10.2.0.8-37sv, 10.2.1.1-19sv, 9.0.0.11-31sv
sonicwall
sma 400 firmware
10.2.0.8-37sv, 10.2.1.1-19sv, 9.0.0.11-31sv
sonicwall
sma 500v firmware
10.2.0.8-37sv, 10.2.1.1-19sv, 9.0.0.11-31sv

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.2.5
  • V1.2.8
  • V15.2.5

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-27 Platform-independent Applications
addresses: CWE-78

Platform-independent apps typically execute inside a managed runtime or sandbox that restricts direct OS command execution, reducing the ability to exploit OS command injection.

SI-10 Information Input Validation
addresses: CWE-78

Validates inputs to block special elements that would alter OS command execution.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.

PR.PS-02 partial match
prevents

Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.

References