GHSA-chx6-hx7r-mcp5 CVE-2026-55685
React Router: Unauthenticated Denial of Service via Inefficient Route Matching
- Severity
- 8.7 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.71%
- Chance of exploitation in the next 30 days. Higher than 53.49% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Fix
7.18.0- Upgrade react-router to this version or later
Description
This is a follow up to https://github.com/remix-run/react-router/security/advisories/GHSA-8x6r-g9mw-2r78 that covers additional reported scenarios in which the manifest endpoint could be accessed via unauthenticated targeted requests that would put heavy load on the server and slow down response times.
[!NOTE] This only impacts Framework Mode applications. This does not impact your application if you are using Declarative or Data Mode.
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| react-router | >= 7.0.0, < 7.18.0 |
7.18.0 |
| react-router | >= 7.0.0, < 7.18.0 |
7.18.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
react-router npm → 7.18.0
- npm
npm install react-router@7.18.0- yarn
yarn add react-router@7.18.0- pnpm
pnpm add react-router@7.18.0
Severity breakdown
CVSS 4.0 8.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
CWE-407: Inefficient Algorithmic Complexity
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-qwww-vcr4-c8h2 React Router: RSC Mode CSRF Bypass Allows Action Execution Before 400 Response | High | Also affects react-router |
| GHSA-wrjc-x8rr-h8h6 React Router: Open redirect via backslash in <Link> and useNavigate (CVE-2025-68470 bypass) | Medium | Also affects react-router |
| GHSA-jjmj-jmhj-qwj2 React Router: Open redirect leading to XSS | Medium | Also affects react-router |
| GHSA-h8fp-f39c-q6mh React Router: RSCErrorHandler Missing Protocol Validation (XSS) | Medium | Also affects react-router |
| GHSA-337j-9hxr-rhxg React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration | Medium | Also affects react-router |
| GHSA-84g9-w2xq-vcv6 React Router: Potential CSRF via PUT/PATCH/DELETE document requests | Low | Also affects react-router |
| GHSA-8x6r-g9mw-2r78 React Router vulnerable to DoS via unbounded path expansion in __manifest endpoint | High | Also affects react-router |
| GHSA-49rj-9fvp-4h2h React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE | High | Also affects react-router |
Credits: dinhvaren
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