Exploited Ransomware

CVE-2025-55182

React (Meta) React Server Components · Frameworks and libraries

Meta React Server Components Remote Code Execution Vulnerability

At a glance

Exploited. Added to CISA’s catalog of exploited vulnerabilities on December 5, 2025.

Used in ransomware attacks, according to CISA.

Affected product: React (Meta) React Server Components (category Frameworks and libraries, indicative classification). Name in CISA’s catalog: Meta React Server Components.

What should I do?

Apply the patches or mitigations from React (Meta); if none are available, stop using the product. For cloud services, follow the guidance from React (Meta).

Deadline set by CISA for US federal agencies: 7 days (due December 12, 2025). It only binds those agencies, but it is a useful measure of urgency.

The vendor’s specific advisory is listed in the NVD references: CVE-2025-55182 on the NVD website.

Original text of the required action (CISA)

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Timeline

December 3, 2025 Vulnerability published Publication date (NVD)
December 5, 2025 Exploitation confirmed Added to CISA’s KEV catalog
December 12, 2025 CISA deadline Remediation deadline set for US federal agencies

The facts, with their sources

Exploitation confirmed: Yes, on December 5, 2025 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Ransomware: Known use Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Hunt for compromise: Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA required action: Apply the patches or mitigations from React (Meta); if none are available, stop using the product. For cloud services, follow the guidance from React (Meta). Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA deadline: December 12, 2025, 7 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Vulnerability published: December 3, 2025 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Product according to CISA: Meta React Server Components Filed by this site under “Frameworks and libraries” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC

Severity and activity

10.0 / 10 CVSS severity: critical

Score from the vendor or CISA, relayed by the NVD. Collected Sep 29, 2026.

— Probability of exploitation in the next 30 days (EPSS)

FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.

Description

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.

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.

Summary from CISA (KEV catalog).

CERT-FR advisories

CERTFR-2025-ALE-014: [MàJ] Vulnérabilité dans React Server Components (updated February 12, 2026)

Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.

Sources for this page

CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
NVD (NIST): CVSS severity, publication date, description, vendor references.
EPSS (FIRST): probability of exploitation.
CERT-FR: advisories and alerts (in French).
Brand and category: indicative classification by this site (method).