CVSS 8.7 (high) · published 2026-10-14
Nodemailer 3.0.0 before 10.0.13 has a regular expression denial of service in SMTPConnection._actionEHLO, whose four AUTH mechanism detection regexes contain overlapping whitespace sub-patterns that backtrack quadratically. A malicious or man-in-the-middle SMTP server can reply to EHLO with 250-AUTH, a long whitespace run and a non-matching token, blocking the Node.js event loop for tens of seconds to hours before authentication.
Weakness: CWE-1333
Source: NVD CVE-2026-110869
Connect an AI agent to the FixLane MCP server or ask the Telegram bot to check what you have installed against incidents with a verified fixed version.