# CVE-2022-21222: Regular Expression Denial of Service (ReDoS)

- Exploited (CISA KEV): no
- Published: 2022-09-30
- CVSS: 5.3 MEDIUM (v3.1)
- EPSS: 1.9% (80th percentile)

The package css-what before 2.1.3 are vulnerable to Regular Expression Denial of Service (ReDoS) due to the usage of insecure regular expression in the re_attr variable of index.js. The exploitation of this vulnerability could be triggered via the parse function.

## 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 | Rule published | 2023-06-06 | 249 |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### F5

- 2023-06-06 · new · rule 200012083
  > Added: signature 200012083 "css-what ReDoS" (Denial of Service, risk Medium), systems: Node.js. References: CVE-2022-21222.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

"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-2022-21222 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2022-21222