CVE-2025-30218

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

At a glance

Severity: LOW 1.7
EPSS: EPSS 0.43 % · percentile 37 (2026-10-27)
State: PUBLISHED
Published: 2025-04-02
Updated: 2025-10-13
Assigner: GitHub_M
NVD status: Analyzed

Description

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.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	LOW 1.7	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	GitHub_M
CVSS 4.0	LOW 1.7	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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD · security-advisories@github.com (Secondary)
CVSS 3.1	MEDIUM 5.9	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N	NVD · nvd@nist.gov (Primary)

Weaknesses (CWE)

CWE-200

Advisories

GHSA-223j-4rm8-mrmf — Next.js may leak x-middleware-subrequest-id to external hosts

European references

ENISA EUVD · EUVD-2025-9629
GCVE · GCVE-0-2025-30218

CERT-FR advisories

CERTFR-2025-AVI-0896 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:vercel:next.js:12.3.5:*:*:*:*:node.js:*:*
cpe:2.3:a:vercel:next.js:13.5.9:*:*:*:*:node.js:*:*
cpe:2.3:a:vercel:next.js:14.2.25:*:*:*:*:node.js:*:*
cpe:2.3:a:vercel:next.js:15.2.3:*:*:*:*:node.js:*:*

Affected products

Product	Versions
vercel · next.js	affected = 12.3.5 ; affected = 13.5.9 ; affected = 14.2.25 ; affected = 15.2.3

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD