Cross-site scripting in React Router - CVE-2026-33245
Published: June 19, 2026
Vulnerability identifier: #VU134924
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Green
CVE-ID: CVE-2026-33245
CWE-ID: CWE-79
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 execute arbitrary script in the victim's browser.
The vulnerability exists due to cross-site scripting in unstable RSC redirect handling when processing javascript: redirect targets from untrusted sources. A remote attacker can supply a crafted redirect target to execute arbitrary script in the victim's browser.
This only affects applications using the unstable RSC APIs.
How to mitigate CVE-2026-33245
Install security update from vendor's website.