CVE-2026-48928 in Node.js
Summary
by MITRE • 06/26/2026
A inconsistency in Node.js hostname matching can cause a trust-policy bypass in multi-context mTLS setups.
This vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.
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Analysis
by VulDB Data Team • 06/27/2026
This vulnerability represents a critical flaw in Node.js's implementation of hostname verification within mutual transport layer security (mTLS) configurations, specifically impacting multi-context environments where trust policies are enforced through certificate validation. The issue stems from an inconsistency in how Node.js processes hostname matching during TLS handshakes, creating potential bypass opportunities for malicious actors who can exploit this gap to establish connections that should have been rejected based on certificate policies.
The technical root cause involves Node.js's handling of Subject Alternative Name (SAN) and Common Name (CN) fields within X.509 certificates when validating hostnames in mTLS scenarios. When multiple contexts or trust domains are present, the hostname matching algorithm fails to properly enforce strict validation rules, allowing certificates with mismatched hostnames to be accepted in situations where they should be rejected. This inconsistency particularly affects environments where Node.js applications serve as both clients and servers within complex certificate authority structures, creating opportunities for attackers to manipulate certificate validation flows.
The operational impact of this vulnerability is significant in production environments that rely on strict mTLS policies for security isolation between services. Attackers could potentially exploit this weakness to perform man-in-the-middle attacks against applications using Node.js, especially in microservices architectures where multiple services communicate through encrypted channels with certificate-based authentication. The vulnerability affects all currently supported release lines including Node.js 22, 24, and 26, indicating it is a persistent issue across the current stable versions that organizations have widely deployed in production systems.
This flaw aligns with CWE-295 which addresses improper certificate validation and can be categorized under ATT&CK technique T1046 for network service scanning and T1566 for credential access through valid accounts. Organizations using Node.js applications in security-critical environments should immediately evaluate their mTLS implementations and consider implementing additional validation layers or migrating to patched versions of Node.js. The vulnerability demonstrates the importance of consistent certificate validation across all components of a security infrastructure, particularly when dealing with multi-context trust relationships where failure in one component can undermine entire security policies.
Mitigation strategies include updating to patched versions of Node.js as soon as available, implementing additional hostname verification logic at application level, and conducting comprehensive audits of existing mTLS configurations to identify potentially vulnerable service communications. Organizations should also consider deploying certificate monitoring solutions that can detect anomalous certificate usage patterns and implement stricter certificate lifecycle management practices to reduce the attack surface associated with this vulnerability.