CVE-2026-64648
Description
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.
Statement
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 5.4 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | Low | N/A |
| Integrity Impact | None | Low | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Frequently Asked Questions
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