# CVE-2021-23758: Ajax.NET Professional Deserialization of Untrusted Data Vulnerability

- Exploited (CISA KEV): yes, added 2026-08-26
- Published: 2021-12-03
- CVSS: 8.1 HIGH (v3.1)
- EPSS: 82.6% (100th percentile)
- CWE: CWE-502

All versions of package ajaxpro.2 are vulnerable to Deserialization of Untrusted Data due to the possibility of deserialization of arbitrary .NET classes, which can be abused to gain remote code execution.

## 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-2021-23758 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2021-23758