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Medium

Next.js vulnerable to cross-site scripting in App Router applications using CSP nonces

  • Disclosed: 11.05.2026
  • Updated: 11.10.2026 10:22

Impact

App Router applications that rely on CSP nonces can be vulnerable to stored cross-site scripting when deployed behind shared caches. In affected versions, malformed nonce values derived from request headers could be reflected into rendered HTML in an unsafe way, allowing an attacker to poison cached responses and cause script execution for later visitors.

Fix

We now reject or ignore malformed nonce values before they are embedded into HTML and apply stricter nonce sanitization so request-derived nonce data cannot break out of the intended attribute context.

Workarounds

If you cannot upgrade immediately, strip inbound Content-Security-Policy request headers from untrusted traffic.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package next >= 13.4.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5

References

CVSS score 4.7/10
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE)
CWE-79
Platform
npm
Package
next
Disclosed
11.05.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-ffhc-5mcf-pf4q - 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 cross-site scripting in App Router applications using CSP nonces this entry
    Medium · 4.7 CVE-2026-44581 >= 13.4.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5
  11. 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
  12. 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
  13. Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes
    High · 7.5 CVE-2026-44575 >= 15.2.0, < 15.5.16, >= 16.0.0, < 16.2.5 15.5.16, 16.2.5
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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
Show more (13) Showing 20 of 33

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