CVE-2026-44573 Details
Description
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.
A vulnerability exists in Next.js applications using the Pages Router with internationalization (i18n) configured, along with middleware or proxy-based authorization. In these applications, unauthorized access to protected page data can be gained through locale-less data requests. The issue arises because middleware does not execute for the unprefixed data route, allowing attackers to obtain server-side rendered JSON for protected pages without the necessary authorization. This vulnerability affects Next.js versions 12.2.0 prior to 15.5.16 and 16.0.0 prior to 16.2.5.
Users can upgrade to Next.js versions 15.5.16 or 16.2.5 to address this vulnerability. If an immediate upgrade is not possible, authorization should be enforced in the page's server-side data path instead of relying solely on middleware.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 13, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://access.redhat.com/errata/RHSA-2026:34608 | redhat-SADP | |
| https://access.redhat.com/errata/RHSA-2026:37272 | redhat-SADP | |
| https://access.redhat.com/errata/RHSA-2026:40974 | redhat-SADP | |
| https://access.redhat.com/errata/RHSA-2026:54435 | redhat-SADP | |
| https://access.redhat.com/security/cve/CVE-2026-44573 | redhat-SADP | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2477199 | redhat-SADP | |
| https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44573.json | redhat-SADP | |
| https://github.com/vercel/next.js/security/advisories/GHSA-36qx-fr4f-26g5 | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-551 | Incorrect Behavior Order: Authorization Before Parsing and Canonicalization | redhat-SADP |
| CWE-863 | Incorrect Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| vercel next.js | >= 12.2.0, < 15.5.16 >= 16.0.0, < 16.2.5 |
CPE
Remediation
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Change History
10 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 13, 2026 | CVE Modified | redhat-SADP |
| Jul 16, 2026 | CVE Modified | redhat-SADP |
| Jul 15, 2026 | CVE Modified | redhat-SADP |
| Jul 10, 2026 | CVE Modified | redhat-SADP |
| Jul 3, 2026 | CVE Modified | redhat-SADP |
| Jun 30, 2026 | CVE Modified | redhat-SADP |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 17, 2026 | CVE Modified | [email protected] |
| May 14, 2026 | Initial Analysis | [email protected] |
| May 13, 2026 | New CVE Received | [email protected] |