Remote Code Execution in React Router Framework Mode single-fetch deserialization
CVE-2026-42211 affects React Router versions 7.0.0 through 7.14.1 when used in Framework Mode. The issue is in the single-fetch data transmission mechanism, which uses a vendored fork of turbo-stream v2 to serialize and deserialize complex JavaScript objects between client and server. According to the provided content, the vulnerable logic is in the error-handling path of the single-fetch deserializer, where untrusted serialized error parameters can cause dynamic hydration of specific JavaScript error subtypes and arbitrary constructor instantiation. In practice, this insecure deserialization condition can be chained with an existing prototype pollution vulnerability in the application code in a two-step attack, resulting in unauthorized remote code execution on the server. Applications using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>) are not affected.
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Recent activity
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A remote code execution vulnerability in React Router that requires chaining with an existing prototype pollution flaw to achieve shell access on remote servers.
An insecure deserialization vulnerability in React Router v7's single-fetch mechanism, specifically in the error-handling logic of its vendored turbo-stream v2 deserializer, allowing an unauthenticated remote attacker to instantiate arbitrary constructors via crafted serialized error payloads.
A remote code execution vulnerability in React Router Framework Mode affecting versions 7.0.0 through 7.14.1, where an existing prototype pollution flaw in application code can be leveraged in a two-step attack to achieve unauthorized RCE via external requests.
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Cross-references every affected SKU, including bundled OEM variants.
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