CVE-2026-44581 MEDIUM

CVE-2026-44581: Next.js: Cross-site scripting in App Router applications using CSP nonces

Vendor Vercel
Product next.js
Weakness CWE-79 · XSS
Published May 13, 2026
Last update May 18, 2026

CVSS base score

4.7/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction Required
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

What the vulnerability does

01Description

Next.js is a React framework for building full-stack web applications. From 13.4.0 to before 15.5.16 and 16.2.5, App Router applications that rely on CSP nonces can be vulnerable to stored cross-site scripting when deployed behind shared caches. In affected versions, malformed nonce values derived from request headers could be reflected into rendered HTML in an unsafe way, allowing an attacker to poison cached responses and cause script execution for later visitors. This vulnerability is fixed in 15.5.16 and 16.2.5.

Key dates

02Disclosure timeline

May 13, 2026 CVE published
May 18, 2026 Record updated