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Link to headingSummary
A critical-severity vulnerability in React Server Components (CVE-2025-55182) affects React 19 and frameworks that use it, including Next.js (CVE-2025-66478). Under certain conditions, specially crafted requests could lead to unintended remote code execution.
We created new rules to address this vulnerability and quickly deployed to the Vercel WAF to automatically protect all projects hosted on Vercel at no cost. However, do not rely on the WAF for full protection. Immediate upgrades to a patched version are required. We also worked with the React team to deliver recommendations to the largest WAF and CDN providers.
We still strongly recommend upgrading to a patched version regardless of your hosting provider.
Link to headingImpact
Applications using affected versions of the React Server Components implementation may process untrusted input in a way that allows an attacker to perform remote code execution. The vulnerability is present in versions 19.0, 19.1.0, 19.1.1, and 19.2.0 of the following packages: :
react-server-dom-parcel (19.0.0, 19.1.0, 19.1.1, and 19.2.0)
react-server-dom-webpack (19.0.0, 19.1.0, 19.1.1, and 19.2.0)
react-server-dom-turbopack (19.0.0, 19.1.0, 19.1.1, and 19.2.0)
These packages are included in the following frameworks and bundlers:
Next.js with versions ≥14.3.0-canary.77, ≥15 and ≥16
Other frameworks and plugins that embed or depend on React Server Components implementation (e.g., Vite, Parcel, React Router, RedwoodSDK, Waku)
Link to headingResolution
After creating mitigations to address this vulnerability, we deployed them across our globally-distributed platform to quickly protect our customers. We still recommend upgrading to the latest patched version.
Updated releases of React and affected downstream frameworks include hardened handling of user inputs to prevent unintended behavior. All users should upgrade to a patched version as soon as possible. If you are on Next.js 14.3.0-canary.77 or a later canary release, downgrade to the latest stable 14.x release.
Link to headingFixed in:
React: 19.0.1, 19.1.2, 19.2.1
Next.js: 15.0.5, 15.1.9, 15.2.6, 15.3.6, 15.4.8, 15.5.7, 15.6.0-canary.58, 16.0.7
Frameworks and bundlers using the aforementioned packages should install the latest versions provided by their respective maintainers.
Link to headingCredit
Thanks to Lachlan Davidson for identifying and responsibly reporting the vulnerability, and the Meta Security and React team for their partnership.