Improper Adherence to Coding Standards Affecting nodemailer package, versions >=3.0.0 <10.0.13
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-NODEMAILER-20952995
- published15 Oct 2026
- disclosed15 Oct 2026
- creditStarPlatinu
Introduced: 15 Oct 2026
NewCVE-2026-110870 (opens in a new tab)How to fix?
Upgrade nodemailer to version 10.0.13 or higher.
Overview
nodemailer is an Easy as cake e-mail sending from your Node.js applications
Affected versions of this package are vulnerable to Improper Adherence to Coding Standards in the checkChar method of the Tokenizer class in src/addressparser/index.ts, where operatorExpecting holds a single expected closing character, so once < opens an address scope a following ( is not recognized as an operator and the RFC 5322 comment survives verbatim in the parsed address. An attacker can have a recipient address approved by an application's own domain allow-list check and then sent differently on the wire by supplying a value such as Legit User <user@good-corp.com(x)evil.com>, since the parentheses reach envelope.to and the RCPT TO command unchanged, where a conformant server rejects the transaction and a server that does strip comments resolves a different domain than the validator read. No recovery path applies, because _recoverAddrSpec returns immediately when the address contains no whitespace and the angle bracket path inserts none, and every field funnelling through MimeNode._parseAddresses, including to, cc, bcc, from, replyTo, and an explicit envelope, is affected identically.