vercel next.js up to 15.5.15/16.2.4 Query authentication bypass

Summaryinfo

A vulnerability, which was classified as critical, has been found in vercel next.js up to 15.5.15/16.2.4. This affects an unknown part of the component Query Handler. Performing a manipulation results in authentication bypass. This vulnerability is identified as CVE-2026-44574. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in vercel next.js up to 15.5.15/16.2.4. It has been classified as critical. This affects an unknown functionality of the component Query Handler. The manipulation with an unknown input leads to a authentication bypass vulnerability. CWE is classifying the issue as CWE-288. A product requires authentication, but the product has an alternate path or channel that does not require authentication. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Next.js is a React framework for building full-stack web applications. From 15.4.0 to before 15.5.16 and 16.2.5, applications that rely on middleware to protect dynamic routes can be vulnerable to authorization bypass. In affected deployments, specially crafted query parameters can alter the dynamic route value seen by the page while leaving the visible path unchanged, which can allow protected content to be rendered without passing the expected middleware check. This vulnerability is fixed in 15.5.16 and 16.2.5.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-44574 since 05/06/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 314909 (Next.js Framework 15.4.x < 15.5.16 / 16.x < 16.2.5 Authorization Bypass), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 15.5.16 or 16.2.5 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (314909) and CERT Bund (WID-SEC-2026-1401). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Vercel Next.js

Productinfo

Type

• JavaScript Library

Vendor

• vercel

Name

• next.js

Version

• 15.5.0
• 15.5.1
• 15.5.2
• 15.5.3
• 15.5.4
• 15.5.5
• 15.5.6
• 15.5.7
• 15.5.8
• 15.5.9
• 15.5.10
• 15.5.11
• 15.5.12
• 15.5.13
• 15.5.14
• 15.5.15
• 16.2.0
• 16.2.1
• 16.2.2
• 16.2.3
• 16.2.4

Website

• Product: https://github.com/vercel/next.js/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion