# CVE-2026-44575: Next.js: Middleware / Proxy bypass in App Router applications via segment-prefetch routes

- Exploited (CISA KEV): no
- Published: 2026-05-13
- CVSS: 7.5 HIGH (v3.1)
- EPSS: 1.6% (76th percentile)
- CWE: CWE-288

Next.js is a React framework for building full-stack web applications. From 15.2.0 to before 15.5.16 and 16.2.5, App Router applications that rely on middleware or proxy-based checks for authorization can allow unauthorized access through transport-specific route variants used for segment prefetching. In affected configurations, specially crafted .rsc and segment-prefetch URLs can resolve to the same page without being matched by the intended middleware rule, which can allow protected content to be reached without the expected authorization check. This vulnerability is fixed in 15.5.16 and 16.2.5.

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

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Rule off by default | 2026-05-07 | -6 |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | No public claim | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### Cloudflare

- 2026-05-07 · new · rule 1de95bf6d6374e1099854278e77e4a53 · default Disabled
  > Next.js - Middleware Bypass via Invalid RSC Header - CVE:CVE-2026-44575. Previous action: N/A. New action: Disabled. This is a new detection.
  Source: https://developers.cloudflare.com/changelog/post/2026-05-07-emergency-waf-release/

"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-2026-44575 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2026-44575