Resource exhaustion in React Router - CVE-2026-42342
Published: June 19, 2026
Vulnerability identifier: #VU134919
CSH Severity: Medium
CVSS v4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-42342
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Remix
Affected software:
React Router
React Router
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in the __manifest endpoint when handling crafted requests with unbounded path expansion. A remote attacker can send a specially crafted request to cause a denial of service.
Only React Router Framework Mode applications are affected; Declarative Mode and Data Mode are not impacted.
How to mitigate CVE-2026-42342
Install security update from vendor's website.