CVE-2026-75604: vercel next.js Path Traversal

Vulnerability summary

CVE-2026-75604 is a critical (CVSS 9.0) Path Traversal vulnerability in vercel next.js. EPSS estimates a 2.10% chance of exploitation in the next 30 days, higher than 81.4% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 01-09-2026
   PublishedVulnerability first disclosed.
2. 04-09-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')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.