Is CVE-2026-55685 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-55685 being exploited in the wild.

How severe is CVE-2026-55685?

High severity, with a CVSS score of 4, published 27 July 2026.

Which products and versions are affected?

React-Router SEMVER:introduced=7.0.0,fixed=7.18.0.

Is there a fix for CVE-2026-55685?

Yes. React-Router: upgrade to 7.18.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-55685 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-55685?

Check whether you run React-Router at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-55685: remix-run react-router resource consumption in manifest endpoint

CVE-2026-55685 · Severity: high · CVSS 4 · Published 2026-07-27

React Router, a popular library for managing navigation in React web applications, contains a vulnerability in its manifest endpoint. An unauthenticated attacker can send specially crafted requests to this endpoint to consume excessive server resources. This can lead to significant performance degradation or a complete service outage for legitimate users.

Technologies: React-Router.

Quick answers

Is CVE-2026-55685 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-55685 being exploited in the wild.
How severe is CVE-2026-55685?: High severity, with a CVSS score of 4, published 27 July 2026.
Which products and versions are affected?: React-Router SEMVER:introduced=7.0.0,fixed=7.18.0.
Is there a fix for CVE-2026-55685?: Yes. React-Router: upgrade to 7.18.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-55685 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-55685?: Check whether you run React-Router at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

React-Router: upgrade to 7.18.0 or later

Technical details

A vulnerability classified as uncontrolled resource consumption (CWE-400) and inefficient algorithmic complexity (CWE-407) exists in React Router's manifest endpoint. In affected versions (7.0.0 to 7.17.0), the endpoint can be accessed via unauthenticated network requests that trigger expensive route-matching operations. This allows a remote attacker to perform a Denial of Service (DoS) attack by saturating server CPU/memory. The issue specifically affects applications not using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter). A fix was introduced in version 7.18.0 by optimizing route matching internals and manifest discovery.

Affected products

remix-run react-router >= 7.0.0, < 7.18.0

Identifiers

CVE-2026-55685
GHSA-chx6-hx7r-mcp5

Timeline

2026-06-15: patched: Fix committed to main branch
2026-07-27: advisory: CVE published to NVD

References

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