CVE-2025-30218CWE-200

Next.js may leak x-middleware-subrequest-id to external hosts

Low · published April 2, 2025

CVSS v4.0
1.7
EPSS
0%
Percentile
35.5
In the wild
Unconfirmed
What it is

Next.js is a React framework for building full-stack web applications. 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. This vulnerability is fixed in 12.3.6, 13.5.10, 14.2.26, and 15.2.4.

The record
Technical detail
CVSS v4.0
1.7 · LOW
Vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U
EPSS
0.00423 · 35.5th percentile
Weakness
CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor
Published
2025-04-02T21:23Z
EPSS history
Timeline
  • 02 APR 21:23Z
    Next.js may leak x-middleware-subrequest-id to external hosts
    cvelistv5