CVE-2026-42211

React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE

HIGH
8.1
CVSS Score
Published: June 2, 2026 at 06:18 PM UTC
Updated: July 21, 2026 at 07:26 PM UTC
2 products affected across 2 vendorsReact RouterReact Router

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Severity
HIGH8.1
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

React Router is a router for React. In versions 7.0.0 through 7.14.1, when using Framework Mode, a combination of steps could potentially allow unauthorized remote code execution (RCE) through external requests. This attack requires the application code to have an existing prototype pollution vulnerability, which can then be leveraged in a 2-step attack where the second step triggers unauthorized RCE on the remote server. This does not impact applications using Declarative Mode (`<BrowserRouter>`) or Data Mode (`createBrowserRouter/<RouterProvider>`). This is patched in version 7.14.2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

7.0.0 ≤ v < 7.14.2
Affected range stops below 7.14.2, so it looks safe — our inference, not a vendor statement
v < 7.14.2
Affected range stops below 7.14.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-502

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