# CVE-2025-55183: Meta react-server-dom-webpack

- Exploited (CISA KEV): no
- Published: 2025-12-11
- CVSS: 5.3 MEDIUM (v3.1)
- EPSS: 64.2% (99th percentile)

An information leak vulnerability exists in specific configurations of React Server Components versions 19.0.0, 19.0.1 19.1.0, 19.1.1, 19.1.2, 19.2.0 and 19.2.1, including the following packages: react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack. A specifically crafted HTTP request sent to a vulnerable Server Function may unsafely return the source code of any Server Function. Exploitation requires the existence of a Server Function which explicitly or implicitly exposes a stringified argument.

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

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Blocks by default | 2025-12-11 | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | Rule published | 2025-12-12 | 1 |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### Cloudflare

- 2025-12-11 · updated · rule 17c5123f1ac049818765ebf2fefb4e9b · default Block
  > React - Leaking Server Functions - CVE:CVE-2025-55183. Previous action: N/A. New action: Block. This was labeled as Generic - Server Function Source Code Exposure.
  Source: https://developers.cloudflare.com/changelog/post/2025-12-11-emergency-waf-release/
- 2025-12-11 · updated · rule 3114709a3c3b4e3685052c7b251e86aa · default Block
  > React - Leaking Server Functions - CVE:CVE-2025-55183. Previous action: N/A. New action: Block. This was labeled as Generic - Server Function Source Code Exposure.
  Source: https://developers.cloudflare.com/changelog/post/2025-12-11-emergency-waf-release/

### F5

- 2025-12-12 · new · rule 200009348
  > Added: signature 200009348 "Next.js Server Function Code Exposure" (Information Leakage, risk Medium), systems: Node.js, JavaScript, ReactJS. References: CVE-2025-55183.
  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-2025-55183 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2025-55183