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 · last modified .
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
EPSS: 0.003 (27.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 27.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-v53p-9fqp-m79j) (vendor-advisory)
- VulnCheck Advisory: nodemailer before 10.0.6 Denial of Service via addressparser (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.