Inefficient Algorithmic Complexity Affecting nodemailer package, versions <10.0.6
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-20158380
- published27 Sept 2026
- disclosed26 Sept 2026
- creditUnknown
Introduced: 26 Sep 2026
NewCVE-2026-100700 (opens in a new tab)How to fix?
Upgrade nodemailer to version 10.0.6 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 Inefficient Algorithmic Complexity via the address parser in src/addressparser/index.ts, where the regex /\s*\b[^@\s]+@[^\s]+\b\s*/ was used to search free text for an email address. The [^@\s]+ quantifier causes quadratic backtracking: from every offset it rescans the run up to the next @ and then fails, advancing one character and repeating. An attacker who can supply a long whitespace-free string containing no usable @ character can block the Node.js event loop for tens of seconds, with 273 KB of input producing approximately 43 seconds of blocking.