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High

Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes

  • Disclosed: 11.05.2026
  • Updated: 11.10.2026 10:22

Impact

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.

Fix

We now include App Router transport variants when generating middleware matchers, so middleware protections are applied consistently to those requests as well as to the normal page URL.

Workarounds

If you cannot upgrade immediately, enforce authorization in the underlying route or page logic instead of relying solely on middleware.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package next >= 15.2.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5

References

CVSS score 7.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE)
CWE-288
Platform
npm
Package
next
Disclosed
11.05.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-267c-6grr-h53f - CC BY 4.0

Vulnerability history: next

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (73) in the archive
Total entries
73
First → latest
12.2017 10.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 5
  • High 27
  • Medium 32
  • Low 9

Disclosures per year

Severity:
  1. Next.js has Server-Side Request Forgery in Image Optimization
    High · 6.5 CVE-2026-94483 >= 16.0.0, < 16.3.8 16.3.8
  2. Next.js: Remote Code Execution in next/og ImageResponse
    Critical ghsa-vcvr-r3jv-pc5j >= 16.2.0, < 16.3.6 16.3.6
  3. Next.js: Unauthenticated Remote Code Execution in Image Optimization API when AVIF files are used
    Critical ghsa-2xp9-vwfh-vxw4 >= 10.0.0, < 15.5.24, >= 16.0.0, < 16.3.3 15.5.24, 16.3.3
  4. Next.js: Unauthenticated Remote Code Execution on windows-hosted servers
    Critical · 9.0 CVE-2026-75604 >= 13.4.0, < 15.5.24, >= 16.0.0, < 16.3.3 15.5.24, 16.3.3
  5. Next.js: Server-Side Request Forgery in Server Actions on custom servers
    High CVE-2026-64649 >= 14.1.1, < 15.5.21, >= 16.0.0, < 16.2.11 15.5.21, 16.2.11
  6. Next.js: Server-Side Request Forgery in rewrites via attacker-controlled destination hostname
    High CVE-2026-64645 >= 12.0.0, < 15.5.21, >= 16.0.0, < 16.2.11 15.5.21, 16.2.11
  7. Next.js: Middleware / Proxy bypass in App Router applications using Turbopack and single locale
    High CVE-2026-64642 >= 16.0.0, < 16.2.11 16.2.11
  8. Next.js: Denial of Service in App Router using Server Actions
    High CVE-2026-64641 >= 13.0.0, < 15.5.21, >= 16.0.0, < 16.2.11 15.5.21, 16.2.11
  9. Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes - Incomplete Fix Follow-Up
    High · 7.5 CVE-2026-45109 >= 15.2.0, < 15.5.18, >= 16.0.0, < 16.2.6 15.5.18, 16.2.6
  10. Next.js vulnerable to Denial of Service via connection exhaustion in applications using Cache Components
    High · 7.5 CVE-2026-44579 >= 15.0.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5
  11. Next.js vulnerable to server-side request forgery in applications using WebSocket upgrades
    High · 8.6 CVE-2026-44578 >= 13.4.13, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5
  12. Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes this entry
    High · 7.5 CVE-2026-44575 >= 15.2.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5
  13. Next.js has a Middleware / Proxy bypass through dynamic route parameter injection
    High · 8.1 CVE-2026-44574 >= 15.4.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5
  14. Next.js has a Middleware / Proxy bypass in Pages Router applications using i18n
    High · 7.5 CVE-2026-44573 >= 12.2.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5
  15. Next.js Vulnerable to Denial of Service with Server Components
    High · 7.5 ghsa-8h8q-6873-q5fj >= 13.0.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5
  16. Next.js has a Denial of Service with Server Components
    High · 7.5 ghsa-q4gf-8mx6-v5v3 >= 13.0.0, < 15.5.15, >= 16.0.0-beta.0, < 16.2.3 15.5.15, 16.2.3
  17. Next.js HTTP request deserialization can lead to DoS when using insecure React Server Components
    High · 7.5 ghsa-h25m-26qc-wcjf >= 13.0.0, < 15.0.8, >= 15.1.1-canary.0, < 15.1.12, >= 15.2.0-canary.0, < 15.2.9, >= 15.3.0-canary.0, < 15.3.9, >= 15.4.0-canary.0, < 15.4.11, >= 15.5.1-canary.0, < 15.5.10, >= 15.6.0-canary.0, < 15.6.0-canary.61, >= 16.0.0-beta.0, < 16.0.11, >= 16.1.0-canary.0, < 16.1.5 15.0.8, 15.1.12, 15.2.9, 15.3.9, 15.4.11, 15.5.10, 15.6.0-canary.61, 16.0.11, 16.1.5
  18. Next has a Denial of Service with Server Components - Incomplete Fix Follow-Up
    High · 7.5 ghsa-5j59-xgg2-r9c4 >= 13.3.1-canary.0, < 14.2.35, >= 15.0.6, < 15.0.7, >= 15.1.10, < 15.1.11, >= 15.2.7, < 15.2.8, >= 15.3.7, < 15.3.8, >= 15.4.9, < 15.4.10, >= 15.5.8, < 15.5.9, >= 15.6.0-canary.59, < 15.6.0-canary.60, >= 16.0.9, < 16.0.10, >= 16.1.0-canary.17, < 16.1.0-canary.19 14.2.35, 15.0.7, 15.1.11, 15.2.8, 15.3.8, 15.4.10, 15.5.9, 15.6.0-canary.60, 16.0.10, 16.1.0-canary.19
  19. Next Vulnerable to Denial of Service with Server Components
    High · 7.5 ghsa-mwv6-3258-q52c >= 13.3.0, < 14.2.34, >= 15.0.0-canary.0, < 15.0.6, >= 15.1.1-canary.0, < 15.1.10, >= 15.2.0-canary.0, < 15.2.7, >= 15.3.0-canary.0, < 15.3.7, >= 15.4.0-canary.0, < 15.4.9, >= 15.5.1-canary.0, < 15.5.8, >= 15.6.0-canary.0, < 15.6.0-canary.59, >= 16.0.0-beta.0, < 16.0.9, >= 16.1.0-canary.0, < 16.1.0-canary.17 14.2.34, 15.0.6, 15.1.10, 15.2.7, 15.3.7, 15.4.9, 15.5.8, 15.6.0-canary.59, 16.0.9, 16.1.0-canary.17
  20. Next.js is vulnerable to RCE in React flight protocol
    Critical · 10.0 ghsa-9qr9-h5gf-34mp >= 14.3.0-canary.77, < 15.0.5, >= 15.1.0-canary.0, < 15.1.9, >= 15.2.0-canary.0, < 15.2.6, >= 15.3.0-canary.0, < 15.3.6, >= 15.4.0-canary.0, < 15.4.8, >= 15.5.0-canary.0, < 15.5.7, >= 16.0.0-canary.0, < 16.0.7 15.0.5, 15.1.9, 15.2.6, 15.3.6, 15.4.8, 15.5.7, 16.0.7
Show more (12) Showing 20 of 32

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