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Advisory record · GHSA-g57g-f23g-4646

Nodemailer: Quoted local-part can produce malformed envelope recipient through RFC 5322 comment parsing

CVSS 6.9 MediumEPSS 0.0023 · 14th percentile

Published by the GitHub Advisory Database at 29 Sept 2026, 23:44 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
nodemailernpm>=9.1.0, <10.0.910.0.9
Identifiers
GHSA-g57g-f23g-4646 · CVE-2026-100699
Weakness (CWE)
CWE-20 · CWE-436
Tags
Published
29 Sept 2026
Updated
30 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Nodemailer versions 9.1.0 before 10.0.9 mis-parse addresses with a quoted local part followed by an RFC 5322 comment, keeping extra domain-like text that is passed into the SMTP envelope recipient. An attacker who controls the comment content could get a malformed recipient used, though the reporter did not confirm delivery to an unintended party. Upgrade to 10.0.9, the fixed version.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
6.9 Medium 4.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CNA (VulnCheck)
  • CISA KEV Not listed.
  • EPSS 0.0023, the 14th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 13:34 UTC First seen by agentprime
  2. 31 Oct 2026, 13:34 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.