CVE-2025-30218

Public on

Last Modified: UTC

Description

A flaw was found in the Next.js package. To mitigate CVE-2025-29927, Next.js validated the x-middleware-subrequest-id, which persisted across multiple incoming requests. However, this subrequest ID is sent to all requests, even if the destination is not the same host as the Next.js application. Initiating a fetch request to a third party within Middleware will send the x-middleware-subrequest-id to that third party.

A flaw was found in the Next.js package. To mitigate CVE-2025-29927, Next.js validated the x-middleware-subrequest-id, which persisted across multiple incoming requests. However, this subrequest ID is sent to all requests, even if the destination is not the same host as the Next.js application. Initiating a fetch request to a third party within Middleware will send the x-middleware-subrequest-id to that third party.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Additional information

  • Bugzilla 2357034: next.js: Next.js may leak x-middleware-subrequest-id to external hosts
  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

Common Vulnerability Scoring System (CVSS) Score Details

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).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

3.7

N/A

Attack Vector

Network

N/A

Attack Complexity

High

N/A

Privileges Required

None

N/A

User Interaction

None

N/A

Scope

Unchanged

N/A

Confidentiality Impact

Low

N/A

Integrity Impact

None

N/A

Availability Impact

None

N/A

CVSS v3 Vector

Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Understanding the Weakness (CWE)

CWE-200

Confidentiality

Technical Impact: Read Application Data

Frequently Asked Questions

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