# CVE-2026-75604: Next.js: Unauthenticated Remote Code Execution on windows-hosted servers

- Exploited (CISA KEV): no
- Published: 2026-09-01
- CVSS: 9 CRITICAL (v3.1)
- EPSS: 2.1% (82th percentile)
- CWE: CWE-22

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.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Blocks by default | 2026-08-26 | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | Rule published | 2026-09-16 | 15 |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### Cloudflare

- 2026-08-26 · updated · rule 2b6b94ec864d47f99630ecf72ca6cce3
  > Next.js - Remote Code Execution - CVE:CVE-2026-75604. Previous action: Block. New action: N/A. Rule metadata description refined. Detection unchanged.
  Source: https://developers.cloudflare.com/changelog/post/2026-08-26-emergency-waf-release/
- 2026-09-08 · updated · rule 771ac3761dcd485cb0e91ea0208457cf · default Block
  > Next.js - Remote Code Execution - CVE:CVE-2026-75604 - Beta. Previous action: Log. New action: Block. This rule is merged into the original rule "Next.js - Remote Code Execution - CVE:CVE-2026-75604" (ID: ...2ca6cce3 ).
  Source: https://developers.cloudflare.com/changelog/post/2026-09-08-waf-release/

### F5

- 2026-09-16 · new · rule 200007122
  > Added: signature 200007122 "Next.js ISR Remote Code Execution" (Path Traversal, risk High), systems: Node.js. References: CVE-2026-75604.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2026-75604 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2026-75604