CVE-2026-64648

A flaw was found in Next.js. A remote attacker could exploit a vulnerability in the server-side fetch mechanism, where a request with a body might receive a cached response intended for a different request to the same URL but different body. This could lead to the unauthorized disclosure of confidential data from POST request response bodies to an unprivileged user.

This Important information disclosure flaw in Next.js arises from a server-side fetch cache confusion, potentially leaking confidential data from POST response bodies to unauthorized requests. The vulnerability is triggered by specific unsafe fetch patterns where the request object's initialization differs from the fetch call's initialization. Red Hat customers using Next.js applications should review their fetch implementations, noting that applications built with Pages Router are not impacted.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.