vercel next.js up to 15.5.23/16.3.2 on Windows Router path traversal

Summaryinfo

A vulnerability was found in vercel next.js up to 15.5.23/16.3.2 on Windows. It has been rated as critical. Affected by this vulnerability is an unknown functionality of the component Router. Performing a manipulation results in path traversal. This vulnerability is known as CVE-2026-75604. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in vercel next.js up to 15.5.23/16.3.2 on Windows. This affects an unknown function of the component Router. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. 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 13.4.0 until 15.5.24 and 16.3.3, Next.js applications using Pages Router or App Router without Cache Components on Windows-hosted servers do not consistently escape backslashes in route segments before constructing incremental-cache paths. In packages/next/src/shared/lib/router/utils/escape-path-delimiters.ts and packages/next/src/server/lib/incremental-cache/file-system-cache.ts, a remote request can supply encoded Windows path separators that traverse outside the intended cache root and expose private build data, including the server-reference-manifest encryption key. Disclosure of that key can enable remote code execution in the affected application. This issue is fixed in versions 15.5.24 and 16.3.3.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-75604. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 342568 (Next.js Framework 13.4 < 15.5.24 / 16.x < 16.3.3 RCE (Windows)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 15.5.24 or 16.3.3 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the vulnerability database at Tenable (342568). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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
• 15.5.16
• 15.5.17
• 15.5.18
• 15.5.19
• 15.5.20
• 15.5.21
• 15.5.22
• 15.5.23
• 16.3.0
• 16.3.1
• 16.3.2

Website

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

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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