CVE-2026-44575

Next.js: Middleware / Proxy bypass in App Router applications via segment-prefetch routes

Published May 13, 2026 CVSS 3.1 · 7.5 High EPSS 1.6% KEV · Not listed
Description
Next.js is a React framework for building full-stack web applications. From 15.2.0 to before 15.5.16 and 16.2.5, App Router applications that rely on middleware or proxy-based checks for authorization can allow unauthorized access through transport-specific route variants used for segment prefetching. In affected configurations, specially crafted .rsc and segment-prefetch URLs can resolve to the same page without being matched by the intended middleware rule, which can allow protected content to be reached without the expected authorization check. This vulnerability is fixed in 15.5.16 and 16.2.5.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-267c-6grr-h53f Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes
History
Type Values Removed Values Added
CPEs cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*
Type Values Removed Values Added
First Time appeared Vercel
Vercel next.js
Vendors & Products Vercel
Vercel next.js
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Next.js is a React framework for building full-stack web applications. From 15.2.0 to before 15.5.16 and 16.2.5, App Router applications that rely on middleware or proxy-based checks for authorization can allow unauthorized access through transport-specific route variants used for segment prefetching. In affected configurations, specially crafted .rsc and segment-prefetch URLs can resolve to the same page without being matched by the intended middleware rule, which can allow protected content to be reached without the expected authorization check. This vulnerability is fixed in 15.5.16 and 16.2.5.
Title Next.js: Middleware / Proxy bypass in App Router applications via segment-prefetch routes
Weaknesses CWE-288
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 13, 2026, 12:04 PM
Reserved
May 6, 2026, 9:49 PM
Status
Modified
Published
May 13, 2026, 5:16 PM
Modified
Oct 26, 2026, 5:10 PM
Severity
Important
Public date
May 13, 2026, 4:54 PM