# CVE-2025-55182: Meta React Server Components Remote Code Execution Vulnerability

- Exploited (CISA KEV): yes, added 2025-12-05, known ransomware use
- Published: 2025-12-03
- CVSS: 10 CRITICAL (v3.1)
- EPSS: 99.8% (100th percentile)

A pre-authentication remote code execution vulnerability exists in React Server Components versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0 including the following packages: react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack. The vulnerable code unsafely deserializes payloads from HTTP requests to Server Function endpoints.

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

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Blocks by default | 2025-12-03 | — |
| AWS | No public claim | — | — |
| Microsoft Azure | Rule published | — | — |
| Google Cloud | Rule published | 2025-12-03 | 0 |
| Fastly | Before feed history | — | — |
| F5 | Rule published | 2025-12-04 | 1 |
| Akamai | No public source | — | — |
| OWASP CRS | Rule published | 2026-01-05 | 33 |

### Cloudflare

- 2025-12-03 · updated · rule 33aa8a8a948b48b28d40450c5fb92fba · default Block
  > React - RCE - CVE:CVE-2025-55182. Previous action: N/A. New action: Block. Rule metadata description changed. Detection unchanged.
  Source: https://developers.cloudflare.com/changelog/post/2025-12-03-emergency-waf-release/
- 2025-12-03 · updated · rule 2b5d06e34a814a889bee9a0699702280 · default Block
  > React - RCE - CVE:CVE-2025-55182. Previous action: N/A. New action: Block. Rule metadata description changed. Detection unchanged.
  Source: https://developers.cloudflare.com/changelog/post/2025-12-03-emergency-waf-release/
- 2025-12-10 · updated · rule bc1aee59731c488ca8b5314615fce168 · default Block
  > React - Remote Code Execution - CVE:CVE-2025-55182 - 2. Previous action: N/A. New action: Block. This is an improved detection.
  Source: https://developers.cloudflare.com/changelog/post/2025-12-10-emergency-waf-release/
- 2025-12-10 · updated · rule cbdd3f48396e4b7389d6efd174746aff · default Block
  > React - Remote Code Execution - CVE:CVE-2025-55182 - 2. Previous action: N/A. New action: Block. This is an improved detection.
  Source: https://developers.cloudflare.com/changelog/post/2025-12-10-emergency-waf-release/

### Microsoft Azure

- undated · listed · rule 99001018
  > Rule 99001018: Critical - 5 · 1 · Attempted React2Shell remote code execution exploitation CVE-2025-55182
  Source: https://learn.microsoft.com/en-us/azure/web-application-firewall/ag/application-gateway-crs-rulegroups-rules
- undated · listed · rule 800115
  > Rule 800115: Critical - 5 · PL1 · Attempted React2Shell remote code execution exploitation CVE-2025-55182
  Source: https://learn.microsoft.com/en-us/azure/web-application-firewall/ag/application-gateway-crs-rulegroups-rules

### Google Cloud

- 2025-12-03 · new · rule cve-canary
  > Security The Cloud Armor cve-canary rules include the google-mrs-v202512-id000001-rce signature to help detect and mitigate CVE-2025-55182 .
  Source: https://docs.cloud.google.com/armor/docs/release-notes#December_03_2025
- 2025-12-06 · new · rule cve-canary
  > Security The Cloud Armor cve-canary rules include the google-mrs-v202512-id000002-rce signature to help detect and mitigate CVE-2025-55182 .
  Source: https://docs.cloud.google.com/armor/docs/release-notes#December_06_2025
- undated · listed · rule google-mrs-v202512-id000001-rce
  > Signature google-mrs-v202512-id000001-rce (sensitivity 0): React RCE vulnerability to help detect and mitigate CVE-2025-55182
  Source: https://docs.cloud.google.com/armor/docs/waf-rules
- undated · listed · rule google-mrs-v202512-id000002-rce
  > Signature google-mrs-v202512-id000002-rce (sensitivity 0): React RCE vulnerability to help detect and mitigate CVE-2025-55182
  Source: https://docs.cloud.google.com/armor/docs/waf-rules

### F5

- 2025-12-04 · new · rule 200204048
  > Added: signature 200204048 "React Server Components RCE" (Server Side Code Injection, risk High), systems: Node.js, JavaScript, ReactJS. References: CVE-2025-55182, CVE-2025-66478.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog
- 2025-12-12 · updated · rule 200204048
  > Updated: signature 200204048 "React Server Components RCE" (Server Side Code Injection, risk High), systems: Node.js, JavaScript, ReactJS. References: CVE-2025-55182, CVE-2025-66478.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog
- 2025-12-12 · updated · rule 200204050
  > Updated: signature 200204050 "Next.js RSC Remote Code Execution" (Server Side Code Injection, risk High), systems: Node.js, JavaScript, ReactJS. References: CVE-2025-55182, CVE-2025-66478.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

### OWASP CRS

- 2026-01-05 · new · rule 934100
  > feat(934100): added sequence for CVE-2025-55182 POCs (https://github.com/coreruleset/coreruleset/pull/4372)
  Source: https://github.com/coreruleset/coreruleset/blob/main/CHANGES.md

## Our test (measured)

- OWASP Core Rule Set 4.25.0, paranoia level 1, anomaly threshold 5, default CRS settings: blocked (2 of 2 requests blocked), template CVE-2025-55182, 2026-11-02
- OWASP Core Rule Set 4.25.0, paranoia level 2, anomaly threshold 5, default CRS settings: blocked (2 of 2 requests blocked), template CVE-2025-55182, 2026-11-02

"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-2025-55182 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2025-55182