CVE-2021-20038
A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-20038- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-121, CWE-787
- Updated
- 2026-11-02
CVE List
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.
- Record
CVE-2021-20038- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-121
- Updated
- 2026-11-02
EUVDEUVD-2021-7501
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.
- Record
EUVD-2021-7501- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-jmhc-vxg9-h2g4
A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module...
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.
- Record
GHSA-jmhc-vxg9-h2g4- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-121, CWE-787
- Updated
- 2026-11-02
CISA KEV No score
SonicWall SMA 100 Appliances Stack-Based Buffer Overflow Vulnerability
SonicWall SMA 100 devies are vulnerable to an unauthenticated stack-based buffer overflow vulnerability where exploitation can result in code execution.
- Record
CVE-2021-20038- Weakness
- CWE-121
- Updated
- 2026-11-02
Affected products
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Metasploit | SonicWall SMA 100 Series Authenticated Command Injection | 2021-12-14 |
| PoC in GitHub | jbaines-r7/badblood | 2022-01-11 |
| PoC in GitHub | vesperp/CVE-2021-20038-SonicWall-RCE | 2022-08-08 |
| PoC in GitHub | anir0y/sonicwall-audit-toolkit | 2026-02-23 |
| Nuclei | SonicWall SMA100 Stack - Buffer Overflow/Remote Code Execution |
History
| Recorded | Changed | Sources |
|---|---|---|
| exploitation, exploits | ||
| first indexed | CVE List, EUVD, GitHub Advisories, CISA KEV, Metasploit, Nuclei, NVD, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-20038 is a critical vulnerability (CVSS 9.8) in Sonicwall Sma100, published December 8, 2021. CISA lists it as known to be exploited, since January 28, 2022. EUVD reports exploitation since January 28, 2022. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 99.9%, the 99th percentile. No source names a fixed version.
References
psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026
github.com/jbaines-r7/badblood
rapid7.com/blog/post/2022/01/11/cve-2021-20038-42-sonicwall-sma-100-multiple-vulnerabilities-fixed-2
cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20038
nvd.nist.gov/vuln/detail/CVE-2021-20038