How severe is CVE-2025-55182?

CVE-2025-55182 has a CVSS score of 10/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-55182?

CVE-2025-55182 affects the following packages: react-server-dom-webpack (npm), react-server-dom-webpack (npm), react-server-dom-webpack (npm), react-server-dom-turbopack (npm), react-server-dom-turbopack (npm), react-server-dom-turbopack (npm), react-server-dom-parcel (npm), react-server-dom-parcel (npm), and 1 more. Ecosystems affected: npm.

How do I fix CVE-2025-55182?

Update react-server-dom-webpack to 19.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-55182 is resolved across your whole dependency graph.

How do I detect CVE-2025-55182 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-server-dom-webpack. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2025-55182 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2025-55182?

O3 pinpoints whether CVE-2025-55182 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2025-55182 actively exploited in the wild?

Yes. There are 117 known exploit references for CVE-2025-55182, including 1 documented proof-of-concept exploit on Exploit-DB. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2025-55182?

CVE-2025-55182 has an EPSS (Exploit Prediction Scoring System) score of 99.6%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2025-55182 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2025-55182 (Meta React Server Components Remote Code Execution Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2025-12-05. CISA required all US federal civilian agencies to remediate this vulnerability by 2025-12-12. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. This CVE has been used in known ransomware campaigns. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2025-55182?

CVE-2025-55182 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2025-55182 published, and has it been updated?

CVE-2025-55182 was published on December 3, 2025 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2025-12-05 — agencies required to remediate by 2025-12-12 · Ransomware

📦 npm

CVE-2025-55182

CRITICAL

React Server Components are Vulnerable to RCE

Also known asGHSA-fv66-9v8q-g76r

Published

Dec 3, 2025

Updated

Jul 8, 2026

Affected

9 pkgs

Patched

9 / 9

Exploits

117 known

EPSS Exploitation Probability

via FIRST.org ↗

99.6%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

9 pkgs affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

react-server-dom-webpacknpm

1.8Mdownloads / week

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.

Affected Packages

9 total 9 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`react-server-dom-webpack`	≥ 19.0.0&&< 19.0.1	19.0.1
📦npm	`react-server-dom-webpack`	≥ 19.1.0&&< 19.1.2	19.1.2
📦npm	`react-server-dom-webpack`	≥ 19.2.0&&< 19.2.1	19.2.1
📦npm	`react-server-dom-turbopack`	≥ 19.0.0&&< 19.0.1	19.0.1
📦npm	`react-server-dom-turbopack`	≥ 19.1.0&&< 19.1.2	19.1.2
📦npm	`react-server-dom-turbopack`	≥ 19.2.0&&< 19.2.1	19.2.1

Exploits & PoCs

117

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-52506webappsmultiple

React Server 19.2.0 - Remote Code Execution

by danieljavanrad · Apr 9, 2026

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-server-dom-webpack. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update react-server-dom-webpack to 19.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-55182 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-55182 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2025-55182. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2025-55182 in your dependencies?

O3 detects CVE-2025-55182 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works