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)

Published · last modified .

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.

EPSS exploit prediction

EPSS: 0.021 (81.4th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 81st percentile — 81.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-75604: held from 0.025 to 0.021.

EPSS over last 30 days · oldest: 0.025 · newest: 0.021 · change: -0.004

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

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?
6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.