How severe is CVE-2025-30218?

No CVSS score has been assigned to CVE-2025-30218 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-30218?

CVE-2025-30218 affects the following packages: next (npm), next (npm), next (npm), next (npm). Ecosystems affected: npm.

How do I fix CVE-2025-30218?

Update next to 12.3.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-30218 is resolved across your whole dependency graph.

How do I detect CVE-2025-30218 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-30218 if there is no patch (or I can't update yet)?

Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Is CVE-2025-30218 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-30218 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-30218?

CVE-2025-30218 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 38th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-30218?

CVE-2025-30218 is classified as Information Exposure (CWE-200). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-30218 published, and has it been updated?

CVE-2025-30218 was published on April 2, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-30218: next — Fixed in 12.3.6

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-30218.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs38th percentile — riskier than 38% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

4 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

61Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

nextnpm

91.6Mdownloads / week

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.

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`next`	≥ 12.3.5&&< 12.3.6	12.3.6`npm install next@12.3.6`
📦npm	`next`	≥ 13.5.9&&< 13.5.10	13.5.10`npm install next@13.5.10`
📦npm	`next`	≥ 14.2.25&&< 14.2.26	14.2.26`npm install next@14.2.26`
📦npm	`next`	≥ 15.2.3&&< 15.2.4	15.2.4`npm install next@15.2.4`

Affected Products

1 product · 4 configurations

Application

next.jsvercel

4 versions

12.3.513.5.914.2.2515.2.3

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update next to 12.3.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-30218 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

Workaround published by Red Hat

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.

Source: Red Hat security advisory for CVE-2025-30218 (CC BY 4.0)

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

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CVE-2025-30218 — next