Exploited vulnerability · CISA KEV

Is CVE-2025-55182 exploited? Yes: in CISA KEV since 5 Dec 2025

Gociux · Meta React Server Components · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2025-55182, Meta React Server Components Remote Code Execution Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 5 Dec 2025, 2 days after it was published. It is known to be used in ransomware campaigns. It affects Meta React Server Components. If you run it, CISA's required action is: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

What it is

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.

What to do

1. Check whether you run it. Look for React Server Components in your asset inventory, including appliances and cloud images. Stack check lists every exploited Meta CVE at once.
2. Apply the fix. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 3 Dec 2025.
4. Get told next time. Email alerts when CISA adds a CVE for Meta.

References

• github.com/vercel-labs/fix-react2shell-next
• nvd.nist.gov/vuln/detail/CVE-2025-55182

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in December 2025 · act-now radar.