SonicWall · SMA 100 Appliances
CVE-2021-20038
SonicWall SMA 100 Appliances Stack-Based Buffer Overflow Vulnerability
What it is
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.
CISA: SonicWall SMA 100 devies are vulnerable to an unauthenticated stack-based buffer overflow vulnerability where exploitation can result in code execution.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: February 11, 2022
More exploited flaws from SonicWall
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Sep 2, 2026 | Server-Side Request Forgery | SMA1000 Appliances | Critical 10.0 | 8.0% |
| Sep 2, 2026 | OS Command Injection | SMA1000 Appliances | High 7.8 | 9.9% |
| Jul 14, 2026 | Server-Side Request Forgery | SMA1000 Appliances | Critical 10.0 | 6.8% |
| Jul 14, 2026 | Code Injection | SMA1000 Appliances | High 7.2 | 12% |
| Dec 17, 2025 | SMA1000 Missing Authorization | SMA1000 appliance | Medium 6.6 | 2.8% |
| May 1, 2025 | OS Command Injection | SMA100 Appliances | High 7.2 | 76% |
| Apr 16, 2025 | OS Command Injection | SMA100 Appliances | Medium 6.5 | 4.4% |
| Feb 18, 2025 | SSLVPN Improper Authentication | SonicOS | High 8.2 | 95% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.