Is CVE-2026-110871 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-110871?

CVE-2026-110871 has a CVSS v3 severity of MEDIUM (6.5).

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CVE-2026-110871

Description

Nodemailer from 3.0.0 before 10.0.10 contains a denial of service vulnerability in MessageParser.parseHeaders that allows users to exhaust CPU through quadratic header unfolding. Attackers can supply large recipient lists or long headers that fold into tens of thousands of continuation lines, blocking the Node.js event loop during DKIM signing.