|
Vulnerabilities
< Back

CVE-2026-64645

Updated on 27 Jul 2026

Severity

8.3 High severity

Details

CVSS score
8.3
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:L/SI:L/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
CWE ID
Links
NISTCIRCLRHELUbuntu

Overview

About vulnerability

Impact

A rewrites() or redirects() rule that builds its external destination hostname from request-controlled input can be pointed at an arbitrary hostname, regardless of the rule’s hostname suffix. For a rewrite, Next.js proxies the request to that arbitrary host and serves the response from the application’s origin, leading to Server-Side Request forgery. A redirects() rule configured this way is vulnerable to an Open Redirect.

This affects any destination that puts a dynamic segment in the hostname, whether from the path:

// next.config.js
module.exports = {
async rewrites() {
return &#91;
{
source: '/:tenant',
destination: 'https://:tenant.api.example.com',
},
&#93;
},
}

or from a has capture:

// next.config.js
module.exports = {
async rewrites() {
return &#91;
{
source: '/',
has: &#91;{ type: 'query', key: 'region', value: '(?&lt;region&gt;.+)' }&#93;,
destination: 'https://:region.api.example.com',
},
&#93;
},
}

Workarounds

If you cannot upgrade immediately, do not build the hostname of an external rewrites() or redirects() destination from user-controlled input. If a dynamic subdomain is required, constrain the value to hostname-safe characters: value: '(?&lt;region&gt;&#91;a-z0-9-&#93;+)'.

Details

Affected product:
Next.js
Affected packages:
eslint-config-next @ 13.5.11 (+52 more)

Fixes