Authenticated protected-content access via route-parameter injection
Published May 13, 2026 · Updated May 13, 2026
Authorization bypass in Vercel Next.js 15.4.0 through 15.5.15 and 16.0.0 through 16.2.4 allows remote authenticated users to read protected content. The App Router accepts externally supplied encodings as internal route parameters, so page resolution diverges from the path checked by middleware. Exploitation requires an application that protects dynamic routes only with middleware; successful requests render content for an attacker-selected route value.
Summary
What happened
Authorization bypass in Vercel Next.js 15.4.0 through 15.5.15 and 16.0.0 through 16.2.4 allows remote authenticated users to read protected content. The App Router accepts externally supplied encodings as internal route parameters, so page resolution diverges from the path checked by middleware. Exploitation requires an application that protects dynamic routes only with middleware; successful requests render content for an attacker-selected route value.
The record
- CVE
- CVE-2026-44574
- Published
- May 13, 2026
- Updated
- May 13, 2026
- Vendor
- Vercel
- Product
- Next.js
- Classifications
- CWE-551, CWE-288, T1190
- Attack vector
- network
- Privileges
- authenticated
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=>= 15.4.0, < 15.5.16
- Affected versionversion=>= 16.0.0, < 16.2.5
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
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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