Authentication bypass via omitted segment-prefetch middleware matchers
Published May 13, 2026 · Updated May 13, 2026
Authentication bypass in Vercel Next.js 15.2.0 through 15.5.17 and 16.0.0 through 16.2.5 allows remote attackers to read protected pages. Turbopack omits middleware.ts matchers for crafted .rsc and segment-prefetch route variants, so those URLs resolve to the page without the intended check. Exposure requires an App Router application that relies on middleware.ts for authorization; the reported consequence is protected-content disclosure only.
Summary
What happened
Authentication bypass in Vercel Next.js 15.2.0 through 15.5.17 and 16.0.0 through 16.2.5 allows remote attackers to read protected pages. Turbopack omits middleware.ts matchers for crafted .rsc and segment-prefetch route variants, so those URLs resolve to the page without the intended check. Exposure requires an App Router application that relies on middleware.ts for authorization; the reported consequence is protected-content disclosure only.
The record
- CVE
- CVE-2026-45109
- Published
- May 13, 2026
- Updated
- May 13, 2026
- Vendor
- Vercel
- Product
- Next.js
- Classifications
- CWE-288, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 13, 2026CVE publishedPublication date reported by the CVE source.
- May 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 15.2.0, < 15.5.17
- Affected versionversion=>= 16.0.0, < 16.2.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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