GHSA-267c-6grr-h53f · Severity: high · Ecosystem: npm — Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes
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.
Conclusion & alert: CVE-2026-44575 is rated Low Risk (35.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-22 | 0.03% | 0.05% | +0.02% |
| 2 | 2026-05-14 | — | 0.03% | — |
Full EPSS history (2 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
GHSA-267c-6grr-h53f · Severity: high · Ecosystem: npm — Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes
| URL | Tags |
|---|---|
| https://github.com/vercel/next.js/security/advisories/GHSA-267c-6grr-h53f | Vendor Advisory |