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Medium

Next.js: Cache confusion of response bodies for requests with bodies containing invalid UTF-8 byte sequences

  • Disclosed: 22.07.2026
  • Updated: 11.10.2026 10:22

Impact

A server-side fetch with a request body may return a cached response body from a different request to the same URL but different body. Confidential data in the POST's response body would then leak to unauthorized requests. Though the request itself will not be deduped.

This is only an issue when receiving request bodies with a content type charset other than UTF-8. For example, the UTF-16 byte sequences for 삃삃 and 섄섄 in the request body would share the same cache.

Workarounds

If you cannot upgrade, consider only making fetch requests with UTF-8 bodies (default in Next.js). Applications using Pages Router are not vulnerable.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package next >= 13.0.0, < 15.5.21, >= 16.0.0, < 16.2.11 15.5.21, 16.2.11

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness (CWE)
CWE-116
Platform
npm
Package
next
Disclosed
22.07.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-4633-3j49-mh5q - 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: Cache confusion of response bodies for requests with bodies containing invalid UTF-8 byte sequences this entry
    Medium CVE-2026-64647 >= 13.0.0, < 15.5.21, >= 16.0.0, < 16.2.11 15.5.21, 16.2.11
  7. 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
  8. 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
  9. 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
  10. 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
  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
  21. 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
  22. Next.JS vulnerability can lead to DoS via cache poisoning
    High · 7.5 CVE-2025-49826 >= 15.0.4-canary.51, < 15.1.8 15.1.8
  23. Authorization Bypass in Next.js Middleware
    Critical · 9.1 CVE-2025-29927 >= 13.0.0, < 13.5.9, >= 14.0.0, < 14.2.25, >= 15.0.0, < 15.2.3, >= 12.0.0, < 12.3.5 13.5.9, 14.2.25, 15.2.3, 12.3.5
  24. Next.js authorization bypass vulnerability
    High · 7.5 CVE-2024-51479 >= 9.5.5, < 14.2.15 14.2.15
  25. Next.js Cache Poisoning
    High · 7.5 CVE-2024-46982 >= 13.5.1, < 13.5.7, >= 14.0.0, < 14.2.10 13.5.7, 14.2.10
  26. Next.js Denial of Service (DoS) condition
    High · 7.5 CVE-2024-39693 >= 13.3.1, < 13.5.0 13.5.0
  27. Next.js Server-Side Request Forgery in Server Actions
    High · 7.5 CVE-2024-34351 >= 13.4.0, < 14.1.1 14.1.1
  28. Next.js Vulnerable to HTTP Request Smuggling
    High · 7.5 CVE-2024-34350 >= 13.4.0, < 13.5.1 13.5.1
  29. Unexpected server crash in Next.js.
    High · 7.5 CVE-2021-43803 >= 12.0.0, < 12.0.5, >= 0.9.9, < 11.1.3 12.0.5, 11.1.3
  30. XSS in Image Optimization API for Next.js
    High · 7.5 CVE-2021-39178 >= 10.0.0, < 11.1.1 11.1.1
  31. Remote Code Execution in next
    High ghsa-5vj8-3v2h-h38v >= 0.9.9, < 5.1.0 5.1.0
  32. Directory traversal vulnerability in Next.js
    High · 7.5 CVE-2018-6184 >= 1.0.0, < 4.2.3 4.2.3
  33. Next.js Directory Traversal Vulnerability
    High · 7.5 CVE-2017-16877 >= 1.0.0, < 2.4.1 2.4.1

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