NetSight
medium5.4

CVE-2026-64648

Next.js is a React framework for building full-stack web applications.

Impact

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 only applies to fetch calls with a request that has a different init than the one passed to fetch. A safe request would be: fetch(new Request(init), init). An unsafe request would be: fetch(new Request(init), aDifferentInit). This issue has been fixed in versions 15.5.21 and 16.2.11.

Affected packages

EcosystemPackageAffectedFixed in
npmnext>= 13.0.0, < 15.5.2115.5.21

Affected products

VendorProductAffected versions
VercelNext.Js
from 12.0.0 before 15.5.21
from 16.0.0 before 16.2.11

Weakness classification

References