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MEDIUM severity

CVE-2025-55183 react-server-dom-parcel

MEDIUM

CVE-2025-55183 is a medium-severity (CVSS 5.3) vulnerability in react-server-dom-parcel. 4 public exploit references exist, so weaponization risk is real. A fix is available for react-server-dom-parcel — see the affected versions and patch details below.

Source Code Exposure Vulnerability in React Server Components

Also known asGHSA-925w-6v3x-g4j4
Published
Dec 11, 2025
Updated
Aug 27, 2026
Affected
9 pkgs
Patched
9 / 9
Exploits
4 known
Exploitation data as of Sep 20, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-55183.

EPSS Exploitation Probability

via FIRST.org ↗
64.2%probability of exploitation in next 30 days
High Risk0.00%
Lower risk than most CVEs99th percentile — riskier than 99% of all scored CVEsHighest risk

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.

How urgent is this, really

CVE-2025-55183 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,238 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

9 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

3other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
react-server-dom-parcelnpm
13Kdownloads / week
react-server-dom-turbopacknpm
28Kdownloads / week
react-server-dom-webpacknpm
1.4Mdownloads / week

Description

An information leak vulnerability exists in specific configurations of React Server Components versions 19.0.0, 19.0.1 19.1.0, 19.1.1, 19.1.2, 19.2.0 and 19.2.1, including the following packages: react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack. A specifically crafted HTTP request sent to a vulnerable Server Function may unsafely return the source code of any Server Function. Exploitation requires the existence of a Server Function which explicitly or implicitly exposes a stringified argument.

Affected Packages

9 total 9 fixed
EcosystemPackageVulnerable rangeFix
📦npmreact-server-dom-parcel19.0.0&&< 19.0.219.0.2npm install react-server-dom-parcel@19.0.2
📦npmreact-server-dom-turbopack19.0.0&&< 19.0.219.0.2npm install react-server-dom-turbopack@19.0.2
📦npmreact-server-dom-webpack19.0.0&&< 19.0.219.0.2npm install react-server-dom-webpack@19.0.2
📦npmreact-server-dom-parcel19.1.0&&< 19.1.319.1.3npm install react-server-dom-parcel@19.1.3
📦npmreact-server-dom-parcel19.2.0&&< 19.2.219.2.2npm install react-server-dom-parcel@19.2.2
📦npmreact-server-dom-turbopack19.1.0&&< 19.1.319.1.3npm install react-server-dom-turbopack@19.1.3
Exploits & PoCs
4

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

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-server-dom-parcel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update react-server-dom-parcel to 19.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-55183 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-55183 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2025-55183. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

An information leak vulnerability exists in specific configurations of React Server Components versions 19.0.0, 19.0.1 19.1.0, 19.1.1, 19.1.2, 19.2.0 and 19.2.1, including the following packages: react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack. A specifically crafted HTTP request sent to a vulnerable Server Function may unsafely return the source code of any Server Function. Exploitation requires the existence of a Server Function which explicitly or implicitly exposes a stringified argument.
O3 Security · Impact-Aware SCA

Is CVE-2025-55183 in your dependencies?

O3 Security finds CVE-2025-55183 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2025-55183: Info Disclosure (Medium 5.3) | O3 Security