CVE-2026-64647
Next.js: Response Body Cache Confusion with Invalid UTF-8 Request Bodies
Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, 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 ์์ and ์์ in the request body would share the same cache. This issue has been fixed in versions 15.5.21 and 16.2.11.
| CWE | CWE-116 |
| Vendor | vercel |
| Product | next.js |
| Published | Jul 27, 2026 |
| Last Updated | Jul 27, 2026 |
Get instant alerts for vercel next.js
Be the first to know when new unknown vulnerabilities affecting vercel next.js are published โ delivered to Slack, Telegram or Discord.