# CVE-2021-27852: Checkbox Survey Deserialization of Untrusted Data Vulnerability

- Exploited (CISA KEV): yes, added 2022-04-11
- Published: 2021-05-27
- CVSS: 9.8 CRITICAL (v3.1)
- EPSS: 30.3% (98th percentile)
- CWE: CWE-502

Deserialization of Untrusted Data vulnerability in CheckboxWeb.dll of Checkbox Survey allows an unauthenticated remote attacker to execute arbitrary code. This issue affects: Checkbox Survey versions prior to 7.

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

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Before feed history | — | — |
| 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 | — | — |

"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-2021-27852 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2021-27852