Vulnerability in Nodemailer
CVE-2026-100700
nodemailer before 10.0.6 contains a denial of service vulnerability in the addressparser free-text fallback regex pattern that exhibits quadratic backtracking behavior. Attackers can supply crafted email header values with long whitespace-free runs to block the Node.js event loop for tens of seconds, causing service unavailability.
Published .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/nodemailer/nodemailer/security/advisories/GHSA-v53p-9fqp-m79j (vendor-advisory)
- www.vulncheck.com/advisories/nodemailer-before-10.0.6-denial-of-service-via-add… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100700?
- CVE-2026-100700 is a high-severity vulnerability in Nodemailer, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-09-26.
- How severe is CVE-2026-100700?
- High severity. CVSS v3 base score is 7.5 out of 10.