CVE-2026-110871Medium· 6.5▾ TwilightPoC availableNodemailer 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…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 35.8 · likelihood 0.1 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Oct 16.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.3%
Exploit / PoC code exists
0.3% → 0.4%
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.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
nodemailer >= 3.0.0, <= 10.0.9Patched in:
nodemailer 10.0.10Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-90776High· 7.5Nodemailer versions 9.1.0 through 10.0.4 contain a quadratic time complexity vulnerability in the addressparser component when parsing email addresses with RFC 5322 comments
GHSA-wxxx-r42m-9rp8High· 6.5Duplicate Advisory: Nodemailer: Quadratic (O(n^2)) DKIM header unfolding lets a large folded header cause remote denial of service during signing
CVE-2026-110872Medium· 5.9Nodemailer from 3.0.0 before 10.0.10 contains a quadratic complexity denial of service vulnerability in the SMTP client reply parser in SMTPConnection._onData and isPartialResponse
GHSA-4g23-2xm8-66gcMedium· 5.9Nodemailer: Quadratic (O(n^2)) SMTP client reply parsing lets a malicious server or MITM cause a pre-auth remote denial of service
CVE-2026-100700High· 7.5nodemailer before 10.0.6 contains a denial of service vulnerability in the addressparser free-text fallback regex pattern that exhibits quadratic backtracking behavior
CVE-2026-92596High· 7.5Nodemailer before 9.1.0 contains a quadratic time complexity vulnerability in the addressparser component that allows remote attackers to cause denial of service by supplying a crafted comma-separated address list