LowGHSA-223j-4rm8-mrmfCVE-2025-30218

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

Published 2 Apr 2025 · Updated 13 Oct 2025

Affected packages

nextnpm

Affected: >=12.3.5 <12.3.6
Fixed in: 12.3.6

Update to the fixed version for your release line, for example:npm install next@12.3.6

nextnpm

Affected: >=13.5.9 <13.5.10
Fixed in: 13.5.10

Update to the fixed version for your release line, for example:npm install next@13.5.10

nextnpm

Affected: >=14.2.25 <14.2.26
Fixed in: 14.2.26

Update to the fixed version for your release line, for example:npm install next@14.2.26

nextnpm

Affected: >=15.2.3 <15.2.4
Fixed in: 15.2.4

Update to the fixed version for your release line, for example:npm install next@15.2.4

Details

Summary

In the process of remediating CVE-2025-29927, we looked at other possible exploits of Middleware. We independently verified this low severity vulnerability in parallel with two reports from independent researchers.

Learn more here.

Credit

Thank you to Jinseo Kim kjsman and RyotaK (GMO Flatt Security Inc.) with takumi-san.ai for the responsible disclosure. These researchers were awarded as part of our bug bounty program.

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References

Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.