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React Router vulnerable to DoS via unbounded path expansion in __manifest endpoint

High severity GitHub Reviewed Published Jun 2, 2026 in remix-run/react-router • Updated Jun 3, 2026

Package

npm @remix-run/server-runtime (npm)

Affected versions

>= 2.10.0, < 2.17.5

Patched versions

2.17.5
npm react-router (npm)
>= 7.0.0, < 7.15.0
7.15.0

Description

There exists a potential DOS attack vector in React Router Framework Mode applications (as well as Remix v2.10.0 - 2.17.4). Certain requests can be crafted to consume disproportionate resources on the server, resulting in response time degredation and/or service unavailability for end users.

Note

This does not impact your React Router application if you are using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>).

References

@brophdawg11 brophdawg11 published to remix-run/react-router Jun 2, 2026
Published by the National Vulnerability Database Jun 2, 2026
Published to the GitHub Advisory Database Jun 3, 2026
Reviewed Jun 3, 2026
Last updated Jun 3, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(22nd percentile)

Weaknesses

Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource. Learn more on MITRE.

CVE ID

CVE-2026-42342

GHSA ID

GHSA-8x6r-g9mw-2r78

Source code

Credits

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