On March 24, 2025, a critical security vulnerability CVE-2025-29927 was disclosed in the Next.js framework, potentially allowing attackers to bypass authentication mechanisms in applications utilizing middleware for security checks.
🔍 Overview of the Vulnerability
- CVE Identifier: CVE-2025-29927
- Severity: Critical (CVSS v3.1 Score: 9.1)
- Affected Versions:
- Next.js 15.x versions prior to 15.2.3
- Next.js 14.x versions prior to 14.2.25
- Next.js 13.x versions prior to 13.5.9
- Next.js 12.x versions prior to 12.3.5
The vulnerability arises from improper authentication handling, where an attacker could craft requests that skip middleware execution, effectively bypassing authentication checks implemented within middleware functions.
🛡️ Recommended Actions
To mitigate this vulnerability:
- Upgrade Next.js: Update to the latest patched versions:
- 15.2.3
- 14.2.25
- 13.5.9
- 12.3.5
- Temporary Mitigation: If immediate upgrading is not feasible, configure your application to block external requests containing the
x-middleware-subrequestheader, preventing potential exploitation.
🧠 Conclusion
This vulnerability underscores the importance of promptly applying security updates and reviewing middleware implementations for critical authentication logic. Developers and organizations using Next.js should assess their applications and ensure they are running secure versions to protect against potential exploitation.
🔗 Additional Resources
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