CISA Known Exploited Vulnerability
This vulnerability is actively exploited in the wild and listed in the CISA Known Exploited Vulnerabilities catalog.
Remediation Deadline: Dec 12, 2025
Description
Meta React Server Components contains a remote code execution vulnerability that could allow unauthenticated remote code execution by exploiting a flaw in how React decodes payloads sent to React Server Function endpoints. Please note CVE-2025-66478 has been rejected, but it is associated with CVE-2025- 55182.
EPSS — Exploit Probability
Higher than 98.7% of all CVEs
Required Action
Check for signs of potential compromise on all internet accessible REACT instances after applying mitigations. For more information, please see: https://react.dev/blog/2025/12/03/critical-security-vulnerability-in-react-server-components ; https://github.com/vercel-labs/fix-react2shell-next?tab=readme-ov-file ; https://nvd.nist.gov/vuln/detail/CVE-2025-55182
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Risk Assessment
CRITICALDetails
- Severity
- High
- EPSS
- 71.1%
- CISA KEV
- Yes
- Ransomware
- Known
- Articles
- 2
Timeline
Published
Dec 5, 2025
Added to KEV
Dec 5, 2025
Remediation Due
Dec 12, 2025