Intel

AIKIDO-2026-10757

next is vulnerable to Authentication Bypass

Authentication BypassGHSA-36qx-fr4f-26g5

75

High Risk

This Affects:

JSnext
12.2.0 - 15.5.15
Fixed in 15.5.16
16.0.0 - 16.2.4
Fixed in 16.2.5
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TL;DR

Pages Router deployments with i18n can expose locale-less data routes that skip middleware checks. An attacker can request internal JSON data endpoints for protected pages without the expected authorization gate. This enables alternate-path access to protected page data. The fix updates matcher behavior so i18n data routes receive equivalent middleware matching.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range.

Background info

next is vulnerable to Authentication Bypass in versions 12.2.0 - 15.5.15 and 16.0.0 - 16.2.4.

How to fix this

Upgrade the next library to the patch version.