Deserialization of Untrusted Data Affecting react-router package, versions >=7.0.0 <7.14.2
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published3 Jun 2026
- disclosed2 Jun 2026
- creditSM41ldRag0n
Introduced: 2 Jun 2026
CVE-2026-42211 (opens in a new tab)How to fix?
Upgrade react-router to version 7.14.2 or higher.
Overview
Affected versions of this package are vulnerable to Deserialization of Untrusted Data via the turbo-stream component in in Framework Mode. An attacker can execute arbitrary code on the remote server by sending specially crafted external requests that exploit an existing prototype pollution issue in the application code.
Note:
Users that are using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>) are not impacted.
Details
Serialization is a process of converting an object into a sequence of bytes which can be persisted to a disk or database or can be sent through streams. The reverse process of creating object from sequence of bytes is called deserialization. Serialization is commonly used for communication (sharing objects between multiple hosts) and persistence (store the object state in a file or a database). It is an integral part of popular protocols like Remote Method Invocation (RMI), Java Management Extension (JMX), Java Messaging System (JMS), Action Message Format (AMF), Java Server Faces (JSF) ViewState, etc.
Deserialization of untrusted data (CWE-502) is when the application deserializes untrusted data without sufficiently verifying that the resulting data will be valid, thus allowing the attacker to control the state or the flow of the execution.