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.
Affected products
vercel: next.js
References8
- github.com/vercel/next.js/security/advisories/GHSA-267c-6grr-h5… Vendor Advisory
- access.redhat.com/errata/RHSA-2026:34608
- access.redhat.com/errata/RHSA-2026:37272
- access.redhat.com/errata/RHSA-2026:40974
- access.redhat.com/errata/RHSA-2026:54435
- access.redhat.com/security/cve/CVE-2026-44575
- bugzilla.redhat.com/show_bug.cgi?id=2477188
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44575…
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - EPSS — exploit probability
- 2% percentile: 76 · as of 14 November 2026
- CWE
- CWE-288CWE-551
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.