# CVE-2026-44573: Next.js: Middleware / Proxy bypass in Pages Router applications using i18n

> CVE-2026-44573: Next.js: Middleware / Proxy bypass in Pages Router applications using i18n. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-44573
Last updated: 2026-08-13T13:19:03Z

- Published: 2026-05-13 16:48 UTC · Updated: 2026-08-13 13:19 UTC · Assigner: GitHub\_M
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS: 0.80%, 56th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-863

## 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.

## Affected vendors and products

- Red Hat: Red Hat Enterprise Linux 10
- Red Hat: Red Hat Enterprise Linux 7
- Red Hat: Red Hat Enterprise Linux 8
- Red Hat: Red Hat Enterprise Linux 9
- Red Hat: Red Hat Enterprise Linux AI (RHEL AI) 3
- Red Hat: Red Hat Trusted Artifact Signer 1.3
- Red Hat: Red Hat Trusted Artifact Signer 1.4
- Red Hat: Streams for Apache Kafka 2.9.4
- Red Hat: streams for Apache Kafka 3
- vercel: next.js

## Tracked companies

- [Vercel](https://rewindex.com/company/vercel.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-44573)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-44573)
- [https://github.com/vercel/next.js/security/advisories/GHSA-36qx-fr4f-26g5](https://github.com/vercel/next.js/security/advisories/GHSA-36qx-fr4f-26g5)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-44573 · Markdown: https://rewindex.com/cve/CVE-2026-44573.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-44573 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:48:28.100Z