CVE-2025-30218

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

Published Apr 2, 2025 CVSS 4.0 · 1.7 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-9629 Next.js may leak x-middleware-subrequest-id to external hosts
Github GHSA Github GHSA GHSA-223j-4rm8-mrmf Next.js may leak x-middleware-subrequest-id to external hosts
History
Type Values Removed Values Added
CPEs 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:*:*
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Type Values Removed Values Added
Metrics epss

{'score': 0.00063}

epss

{'score': 0.00067}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

threat_severity

Low

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Next.js may leak x-middleware-subrequest-id to external hosts
Weaknesses CWE-200
References
Metrics cvssV4_0

{'score': 1.7, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 13, 2025, 3:37 PM
Reserved
Mar 18, 2025, 6:15 PM
Status
Analyzed
Published
Apr 2, 2025, 10:15 PM
Modified
Jun 17, 2026, 9:08 AM
Severity
Low
Public date
Apr 2, 2025, 9:23 PM