{"id":"CVE-2026-110869","published":"2026-10-14T23:17:28.673","lastModified":"2026-10-16T18:14:51.460","description":"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.","cvssScore":7.5,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwes":["CWE-1333"],"vendors":[],"products":[],"references":[{"url":"https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx","tags":[]},{"url":"https://www.vulncheck.com/advisories/nodemailer-3.0.0-before-10.0.13-redos-via-smtp-auth-mechanism-detection-regexes","tags":[]},{"url":"https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx","tags":[]}],"exploitRefs":[{"url":"https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx","tags":[]},{"url":"https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx","tags":[]}],"hasPoc":true,"ai":null}