CVE-2021-20038: SonicWall SMA 100 Appliances Stack-Based Buffer Overflow Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2022-01-28. EPSS: 99.9% chance of exploitation in the next 30 days.

A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module environment variables allows a remote unauthenticated attacker to potentially execute code as a 'nobody' user in the appliance. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances firmware 10.2.0.8-37sv, 10.2.1.1-19sv, 10.2.1.2-24sv and earlier versions.

Affected products

• SonicWall SMA 200 Firmware: version 10.2.0.8-37sv only; version 10.2.1.1-19sv only; version 10.2.1.2-24sv only
• SonicWall SMA 210 Firmware: version 10.2.0.8-37sv only; version 10.2.1.1-19sv only; version 10.2.1.2-24sv only
• SonicWall SMA 400 Firmware: version 10.2.0.8-37sv only; version 10.2.1.1-19sv only; version 10.2.1.2-24sv only
• SonicWall SMA 410 Firmware: version 10.2.0.8-37sv only; version 10.2.1.1-19sv only; version 10.2.1.2-24sv only
• SonicWall SMA 500v Firmware: version 10.2.0.8-37sv only; version 10.2.1.1-19sv only; version 10.2.1.2-24sv only

Published 2021-12-08. Last modified 2026-06-17.