CVE-2021-20039

Name: CVE-2021-20039
Creator: NVD / NIST
Published: 2021-12-08T10:15:07.903+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 78.11%

Last modified Jun 17, 2026

CVE-2021-20039 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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.. EPSS estimates a 78.11% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

78.11%

99.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Sonicwall	Sma 200 Firmware	9.0.0.11-31sv
Sonicwall	Sma 200 Firmware	10.2.0.8-37sv
Sonicwall	Sma 200 Firmware	10.2.1.1-19sv
Sonicwall	Sma 210 Firmware	9.0.0.11-31sv
Sonicwall	Sma 210 Firmware	10.2.0.8-37sv
Sonicwall	Sma 210 Firmware	10.2.1.1-19sv
Sonicwall	Sma 410 Firmware	9.0.0.11-31sv
Sonicwall	Sma 410 Firmware	10.2.0.8-37sv
Sonicwall	Sma 410 Firmware	10.2.1.1-19sv
Sonicwall	Sma 400 Firmware	9.0.0.11-31sv
Sonicwall	Sma 400 Firmware	10.2.0.8-37sv
Sonicwall	Sma 400 Firmware	10.2.1.1-19sv
Sonicwall	Sma 500v Firmware	9.0.0.11-31sv
Sonicwall	Sma 500v Firmware	10.2.0.8-37sv
Sonicwall	Sma 500v Firmware	10.2.1.1-19sv

References

http://packetstormsecurity.com/files/165563/SonicWall-SMA-100-Series-Authenticated-Command-Injection.htmlExploit, Third Party Advisory, VDB Entry
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026Vendor Advisory
http://packetstormsecurity.com/files/165563/SonicWall-SMA-100-Series-Authenticated-Command-Injection.htmlExploit, Third Party Advisory, VDB Entry
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026Vendor Advisory
https://attackerkb.com/topics/9szJhq46lw/cve-2021-20039/rapid7-analysis

Timeline

Published: Dec 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20039?

How severe is CVE-2021-20039?

CVE-2021-20039 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 78.11% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20039?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20039?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST