Next.js is a React framework for building full-stack web applications. From 12.2.0 to before 15.5.16 and 16.2.5, Applications using the Pages Router with i18n configured and middleware/proxy-based authorization can allow unauthorized access to protected page data through locale-less /_next/data/<buildId>/<page>.json requests. In affected configurations, middleware does not run for the unprefixed data route, allowing an attacker to retrieve SSR JSON for protected pages without passing the intended authorization checks. This vulnerability is fixed in 15.5.16 and 16.2.5.
Fix
Patch, vendor advisory and mitigation references on NVD 1
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.5 · vercelNVD modified 2026-10-26 17:10
Affected (CPE criteria) 1
cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*
References 8
- https://github.com/vercel/next.js/security/advisories/GHSA-36qx-fr4f-26g5 Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:34608
- https://access.redhat.com/errata/RHSA-2026:37272
- https://access.redhat.com/errata/RHSA-2026:40974
- https://access.redhat.com/errata/RHSA-2026:54435
- https://access.redhat.com/security/cve/CVE-2026-44573
- https://bugzilla.redhat.com/show_bug.cgi?id=2477199
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44573.json