Path Traversal in Vercel Next.js
CVE-2026-75604
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.
Vulnerability class: Path Traversal (Directory Traversal)
CVSS v3 metric
CVSS v3 base score 9.0 (Critical). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H.
Affected products
- Vercel Next.js — versions >= 13.4.0, < 15.5.24, >= 16.0.0, < 16.3.3
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-75604?
- CVE-2026-75604 is a critical-severity vulnerability in Vercel Next.js, classified under Path Traversal. CVSS score: 9.0/10. Published 2026-09-01.
- How severe is CVE-2026-75604?
- Critical severity. CVSS v3 base score is 9.0 out of 10.
- Is CVE-2026-75604 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.