Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes - Incomplete Fix Follow-Up

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.0085, the 58th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

1. 11 May 2026, 16:21 UTC Confirmed by GitHub Advisory Database
2. 13 May 2026, 17:11 UTC Confirmed by the CVE List
3. 13 May 2026, 18:16 UTC Confirmed by NVD

Sources

• GitHub Advisory Database: GHSA-26hh-7cqf-hhc6
• OSV: GHSA-26hh-7cqf-hhc6
• github.com/vercel/next.js/security/advisories/GHSA-267c-6grr-h53f
• github.com/vercel/next.js/security/advisories/GHSA-26hh-7cqf-hhc6
• nvd.nist.gov/vuln/detail/CVE-2026-45109
• github.com/vercel/next.js
• github.com/vercel/next.js/releases/tag/v15.5.18
• github.com/vercel/next.js/releases/tag/v16.2.6

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.