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.
Conclusion & alert: CVE-2021-20038 is rated Critical Active Threat (100/100): CVSS Critical severity, with high exploitation likelihood (EPSS 99.91%, 100th percentile). Core evidence: CISA KEV confirms active exploitation (added 2022-01-28) affecting SonicWall / SMA 100 Appliances. a weakness (CWE-121) Unauthenticated remote administrative access may be possible. EPSS rose +5.62% over the last day, indicating growing attacker interest. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.
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: SonicWall SMA 100 Appliances Stack-Based Buffer Overflow Vulnerability · CISA KEV detail
: 2022-01-28
: 2022-02-11
: Apply updates per vendor instructions.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ | |
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 94.29% | 99.91% | +5.62% |
| 2 | 2025-11-21 | 94.06% | 94.29% | +0.24% |
| 3 | 2025-11-18 | — | 94.06% | — |
Full EPSS history (49 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| sonicwall | sma_200_firmware | 10.2.0.8-37sv | cpe:2.3:o:sonicwall:sma_200_firmware:10.2.0.8-37sv:*:*:*:*:*:*:* |
| sonicwall | sma_200_firmware | 10.2.1.1-19sv | cpe:2.3:o:sonicwall:sma_200_firmware:10.2.1.1-19sv:*:*:*:*:*:*:* |
| sonicwall | sma_200_firmware | 10.2.1.2-24sv | cpe:2.3:o:sonicwall:sma_200_firmware:10.2.1.2-24sv:*:*:*:*:*:*:* |
| sonicwall | sma_210_firmware | 10.2.0.8-37sv | cpe:2.3:o:sonicwall:sma_210_firmware:10.2.0.8-37sv:*:*:*:*:*:*:* |
| sonicwall | sma_210_firmware | 10.2.1.1-19sv | cpe:2.3:o:sonicwall:sma_210_firmware:10.2.1.1-19sv:*:*:*:*:*:*:* |
| sonicwall | sma_210_firmware | 10.2.1.2-24sv | cpe:2.3:o:sonicwall:sma_210_firmware:10.2.1.2-24sv:*:*:*:*:*:*:* |
| sonicwall | sma_410_firmware | 10.2.0.8-37sv | cpe:2.3:o:sonicwall:sma_410_firmware:10.2.0.8-37sv:*:*:*:*:*:*:* |
| sonicwall | sma_410_firmware | 10.2.1.1-19sv | cpe:2.3:o:sonicwall:sma_410_firmware:10.2.1.1-19sv:*:*:*:*:*:*:* |
| sonicwall | sma_410_firmware | 10.2.1.2-24sv | cpe:2.3:o:sonicwall:sma_410_firmware:10.2.1.2-24sv:*:*:*:*:*:*:* |
| sonicwall | sma_400_firmware | 10.2.0.8-37sv | cpe:2.3:o:sonicwall:sma_400_firmware:10.2.0.8-37sv:*:*:*:*:*:*:* |
| sonicwall | sma_400_firmware | 10.2.1.1-19sv | cpe:2.3:o:sonicwall:sma_400_firmware:10.2.1.1-19sv:*:*:*:*:*:*:* |
| sonicwall | sma_400_firmware | 10.2.1.2-24sv | cpe:2.3:o:sonicwall:sma_400_firmware:10.2.1.2-24sv:*:*:*:*:*:*:* |
| sonicwall | sma_500v_firmware | 10.2.0.8-37sv | cpe:2.3:o:sonicwall:sma_500v_firmware:10.2.0.8-37sv:*:*:*:*:*:*:* |
| sonicwall | sma_500v_firmware | 10.2.1.1-19sv | cpe:2.3:o:sonicwall:sma_500v_firmware:10.2.1.1-19sv:*:*:*:*:*:*:* |
| sonicwall | sma_500v_firmware | 10.2.1.2-24sv | cpe:2.3:o:sonicwall:sma_500v_firmware:10.2.1.2-24sv:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://github.com/jbaines-r7/badblood | Exploit Third Party Advisory |
| https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026 | Vendor Advisory |
| https://www.rapid7.com/blog/post/2022/01/11/cve-2021-20038-42-sonicwall-sma-100-multiple-vulnerabilities-fixed-2/ | Exploit Third Party Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20038 | US Government Resource |