# CVE-2023-21554: Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability

- Exploited (CISA KEV): no
- Published: 2023-04-11
- CVSS: 9.8 CRITICAL (v3.1)
- EPSS: 95.4% (100th percentile)
- CWE: CWE-20

Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability

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

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Blocks by default | 2025-01-06 | 636 |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | Before feed history | — | — |
| Fastly | Before feed history | — | — |
| F5 | No public claim | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### Cloudflare

- 2025-01-06 · new · rule b490d6edcfec4028aef45cf08aafb2f5 · default Block
  > MSMQ Service - Remote Code Execution - CVE:CVE-2023-21554. Previous action: Log. New action: Block. New Detection
  Source: https://developers.cloudflare.com/changelog/post/2025-01-06-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-2023-21554 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2023-21554