# CVE-2021-20040: SonicWall SonicWall SMA100

- Exploited (CISA KEV): no
- Published: 2021-12-08
- CVSS: not scored
- EPSS: 25.1% (98th percentile)
- CWE: CWE-23

A relative path traversal vulnerability in the SMA100 upload funtion allows a remote unauthenticated attacker to upload crafted web pages or files as a 'nobody' user. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Blocks by default | 2025-05-05 | 1244 |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | Before feed history | — | — |
| Fastly | Before feed history | — | — |
| F5 | Before feed history | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | Before feed history | — | — |

### Cloudflare

- 2025-05-05 · new · rule 616ad0e03892473191ca1df4e9cf745d · default Block
  > SonicWall SMA - Dangerous File Upload - CVE:CVE-2021-20040, CVE:CVE-2021-20041, CVE:CVE-2021-20042. Previous action: Log. New action: Block. This is a New Detection
  Source: https://developers.cloudflare.com/changelog/post/2025-05-05-waf-release/

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2021-20040 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2021-20040