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CVE-2026-44573

Next.js: Middleware / Proxy bypass in Pages Router applications using i18n

Published: May 13, 2026Updated: May 14, 2026 Sources: CVE List NVD BDUCWE-863
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.4%
Top 73.2%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-863

Affected Products

next.jsvercel
LibraryLibrary
OSS Libraries / web-framework
Next.jsVercel
LibraryLibrary
OSS Libraries / web-framework
vercelcommercialUSOSS Librariesaka vercel

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Initial Access
View detailed technique mapping

References

https://github.com/vercel/next.js/security/advisories/GHSA-36qx-fr4f-26g5
github.com
https://github.com/vercel/next.js/security/advisories/GHSA-36qx-fr4f-26g5&#13;
github.com
https://github.com/dwisiswant0/next-16.2.4-pocs
github.com

Timeline

Published
May 13, 2026
Last Updated
May 14, 2026

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