React Server Components have a Denial of Service VulnerabilityGHSA-479c-33wc-g2pg
HIGHGHSA-479c-33wc-g2pg is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in react-server-dom-parcel. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for react-server-dom-parcel — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-479c-33wc-g2pg.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
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.
react-server-dom-parcelnpmDescription
Impact
A denial of service vulnerability exists in React Server Components, affecting the following packages: react-server-dom-parcel, react-server-dom-turbopack, react-server-dom-webpack versions 19.0.0, 19.1.0 and 19.2.0. The vulnerability is triggered by sending specially crafted HTTP requests to Server Function endpoints.
The payload of the HTTP request causes excessive CPU usage for up to a minute ending in a thrown error that is catchable.
We recommend updating immediately.
The vulnerability exists in versions 19.0.0 through 19.0.4, 19.1.0 through 19.1.5, and 19.2.0 through 19.2.4 of:
react-server-dom-webpack react-server-dom-parcel react-server-dom-turbopack
Patches
Fixes were back ported to versions 19.0.5, 19.1.6, and 19.2.5.
If you are using any of the above packages please upgrade to any of the fixed versions immediately.
If your app’s React code does not use a server, your app is not affected by this vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability.
References
See the blog post for more information and upgrade instructions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | react-server-dom-parcel | ≥ 19.0.0&&< 19.0.5 | 19.0.5npm install react-server-dom-parcel@19.0.5 |
| 📦npm | react-server-dom-parcel | ≥ 19.1.0&&< 19.1.6 | 19.1.6npm install react-server-dom-parcel@19.1.6 |
| 📦npm | react-server-dom-parcel | ≥ 19.2.0&&< 19.2.5 | 19.2.5npm install react-server-dom-parcel@19.2.5 |
| 📦npm | react-server-dom-turbopack | ≥ 19.0.0&&< 19.0.5 | 19.0.5npm install react-server-dom-turbopack@19.0.5 |
| 📦npm | react-server-dom-turbopack | ≥ 19.1.0&&< 19.1.6 | 19.1.6npm install react-server-dom-turbopack@19.1.6 |
| 📦npm | react-server-dom-turbopack | ≥ 19.2.0&&< 19.2.5 | 19.2.5npm install react-server-dom-turbopack@19.2.5 |
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 dependencyDetect
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.
Fix
Update react-server-dom-parcel to 19.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-479c-33wc-g2pg is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Applications are not vulnerable to this issue if they do not use a server, or if they do not use a framework, bundler, or plugin that supports React server components. This vulnerability allows an unauthenticated remote attacker to cause a denial of service. Due to these reasons, this flaw has been rated with an…
Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possibleSource: Red Hat security advisory for GHSA-479c-33wc-g2pg (CC BY 4.0)
Frequently Asked Questions
Is GHSA-479c-33wc-g2pg in your dependencies?
Find it across npm, including transitive dependencies.