CVE-2026-55685
React Router: Unauthenticated Denial of Service via Inefficient Route Matching
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.
INFO
Published Date :
July 27, 2026, 10:17 p.m.
Last Modified :
Aug. 3, 2026, 1:56 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update React Router to version 7.18.0.
- Verify application uses Declarative or Data Mode.
- Monitor server load after update.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55685.
| URL | Resource |
|---|---|
| https://github.com/remix-run/react-router/blob/main/CHANGELOG.md#v7180 | Release Notes |
| https://github.com/remix-run/react-router/commit/09e6020d1950e54f361f7ad00938ecd4dde60929 | Patch |
| https://github.com/remix-run/react-router/pull/15186 | Issue Tracking Patch |
| https://github.com/remix-run/react-router/releases/tag/[email protected] | Release Notes |
| https://github.com/remix-run/react-router/security/advisories/GHSA-8x6r-g9mw-2r78 | Third Party Advisory |
| https://github.com/remix-run/react-router/security/advisories/GHSA-chx6-hx7r-mcp5 | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55685 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55685
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55685 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55685 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Aug. 03, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:shopify:react-router:*:*:*:*:*:node.js:*:* versions from (including) 7.0.0 up to (excluding) 7.18.0 Added Reference Type GitHub, Inc.: https://github.com/remix-run/react-router/blob/main/CHANGELOG.md#v7180 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/remix-run/react-router/commit/09e6020d1950e54f361f7ad00938ecd4dde60929 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/remix-run/react-router/pull/15186 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/remix-run/react-router/releases/tag/[email protected] Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/remix-run/react-router/security/advisories/GHSA-8x6r-g9mw-2r78 Types: Third Party Advisory Added Reference Type GitHub, Inc.: https://github.com/remix-run/react-router/security/advisories/GHSA-chx6-hx7r-mcp5 Types: Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 28, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-55685', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-28T13:39:39.469503Z'} -
New CVE Received by [email protected]
Jul. 27, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'remix-run', 'product': 'react-router', 'versions': [{'status': 'affected', 'version': '>= 7.0.0, < 7.18.0'}]}] Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-407 Added CWE CWE-400 Added Reference https://github.com/remix-run/react-router/blob/main/CHANGELOG.md#v7180 Added Reference https://github.com/remix-run/react-router/commit/09e6020d1950e54f361f7ad00938ecd4dde60929 Added Reference https://github.com/remix-run/react-router/pull/15186 Added Reference https://github.com/remix-run/react-router/releases/tag/[email protected] Added Reference https://github.com/remix-run/react-router/security/advisories/GHSA-8x6r-g9mw-2r78 Added Reference https://github.com/remix-run/react-router/security/advisories/GHSA-chx6-hx7r-mcp5