nodemailer before 6.9.9 contains a regular expression denial of service vulnerability in email parsing when attachDataUrls parameter is set or processing embedded file attachments. Attackers can send specially crafted emails with malicious data URLs or embedded attachments to cause the event loop to hang and deny service.
https://www.vulncheck.com/advisories/nodemailer-before-6.9.9-redos-via-attachdataurls-parameter
https://github.com/nodemailer/nodemailer/security/advisories/GHSA-9h6g-pr28-7cqp
Published: 2026-08-31
Updated: 2026-08-31
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
Severity: Medium
Base Score: 5.3
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Severity: Medium
Base Score: 6.9
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00304