CVE-2025-14874 in nodemailer
Summary
by MITRE • 12/18/2025
A flaw was found in Nodemailer. This vulnerability allows a denial of service (DoS) via a crafted email address header that triggers infinite recursion in the address parser.
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Analysis
by VulDB Data Team • 03/18/2026
The vulnerability identified as CVE-2025-14874 represents a critical denial of service flaw within the Nodemailer email processing library. This issue stems from inadequate input validation in the email address header parsing mechanism, where specifically crafted email addresses can trigger infinite recursive parsing operations. The vulnerability affects applications that rely on Nodemailer for email processing and can potentially disrupt service availability when maliciously constructed email headers are processed. The flaw demonstrates a classic example of improper input validation that leads to resource exhaustion and system instability.
The technical implementation of this vulnerability occurs within the address parser component of Nodemailer where the software fails to properly terminate recursive parsing operations when encountering malformed email address headers. When a specially crafted email header contains nested or self-referential address structures, the parser enters an infinite recursion loop that consumes system resources and ultimately leads to process termination or system unresponsiveness. This behavior maps directly to CWE-674 which categorizes improper handling of recursive data structures and CWE-400 which covers unspecified denial of service conditions. The vulnerability operates at the application layer and can be exploited through simple email header manipulation without requiring authentication or elevated privileges.
From an operational perspective, this vulnerability presents significant risk to email processing systems that handle untrusted input from external sources. Attackers can exploit this weakness by sending emails containing maliciously constructed headers that trigger the infinite recursion, causing the target application to consume excessive CPU cycles and memory resources. The impact extends beyond simple service disruption as it can affect entire email servers, web applications, and automated email processing systems that depend on Nodemailer. This vulnerability aligns with ATT&CK technique T1499 which covers resource exhaustion attacks and demonstrates how seemingly benign input processing can become a vector for system compromise.
Organizations utilizing Nodemailer should implement immediate mitigations including input validation measures, rate limiting for email processing, and application-level monitoring to detect unusual resource consumption patterns. The most effective remediation involves updating to patched versions of Nodemailer where proper recursion limits and input sanitization have been implemented. Additionally, implementing proper email header validation and sanitization at the network level can provide additional defense in depth. Security teams should also consider deploying intrusion detection systems capable of identifying patterns associated with this specific vulnerability and establish incident response procedures to handle potential exploitation attempts. The vulnerability underscores the importance of proper input validation and recursion handling in email processing systems, particularly those handling untrusted external data sources.