CVE-2026-55685

React Router: Unauthenticated Denial of Service via Inefficient Route Matching

HIGH
7.5
CVSS Score
Published: July 27, 2026 at 09:45 PM UTC
Updated: October 24, 2026 at 01:10 PM UTC
2 products affected across 2 vendorsReact RouterReact Router

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Severity
HIGH7.5
Exploit prediction
EPSS 0.7%
SSVC
No known exploit

Description

React Router is a router for React. In versions 7.0.0 through 7.17.0, the manifest endpoint could be accessed via unauthenticated targeted requests that would put heavy load on the server and slow down response times. This issue is a follow up to CVE-2026-42342, and does not does not impact React Router applications using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>). This issue has been fixed in version 7.18.0.

Affected

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

All versions7.0.0 ≤ v < 7.18.0
Affected range stops below 7.18.0, so it looks safe — our inference, not a vendor statement
Affected range stops below 7.18.0, 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 (6)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

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

CVSS

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

Quick Info

StatusANALYZED
CWE
CWE-400CWE-407

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