CVE-2026-45109

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

State: Published
Severity: 7.5 High
Published: May 13, 2026
Updated: Aug 13, 2026
Reserved: May 8, 2026

Description

Next.js is a React framework for building full-stack web applications. From 15.2.0 to before 15.5.18 and 16.2.6, it was found that the fix addressing CVE-2026-44575 did not apply to middleware.ts with Turbopack. This vulnerability is fixed in 15.5.18 and 16.2.6.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	GitHub_M
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	redhat-SADP

Weaknesses

CWE-288 Authentication Bypass Using an Alternate Path or Channel
CWE-358 Improperly Implemented Security Check for Standard

Affected Products

Product	Versions
next.jsvercel	>= 15.2.0, < 15.5.17Affected >= 16.0.0, < 16.2.6Affected

References

https://github.com/vercel/next.js/security/advisories/GHSA-26hh-7cqf-hhc6
https://access.redhat.com/security/cve/CVE-2026-45109vdb-entry
RHBZ#2477190issue-tracking
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45109.json
https://access.redhat.com/errata/RHSA-2026:40974vendor-advisory
https://access.redhat.com/errata/RHSA-2026:37272vendor-advisory
https://access.redhat.com/errata/RHSA-2026:34608vendor-advisory
https://access.redhat.com/errata/RHSA-2026:54435vendor-advisory

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