Nodemailer is a Node.js email-sending library. In versions >= 9.1.0 and < 10.0.9, the address parser (src/addressparser) mishandles addresses whose local-part is a quoted string and that are followed by RFC 5322 comments, allowing trailing comment-separated domain atoms to be retained in the normalized address. For example, the input "user"@example.com(x)evil.com is parsed to the address value 'user@example.com evil.com', which contains additional attacker-controlled domain text separated by a literal space. This parsed value is used without further strict recipient validation when the message envelope is built (envelope.to in src/mime-node), so a malformed/ambiguous recipient address can be accepted and placed in the SMTP envelope. Whether this results in delivery to an unintended recipient on real SMTP servers has not been confirmed. The issue is a variant of the RFC 5322 comment parsing problem addressed in GHSA-cc9r-2j5m-2m83, affecting the separate quoted-local-part code path. Version 10.0.9 contains a fix.
Advisories
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Fixes
Solution
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Workaround
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References
History
Sat, 26 Sep 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Nodemailer is a Node.js email-sending library. In versions >= 9.1.0 and < 10.0.9, the address parser (src/addressparser) mishandles addresses whose local-part is a quoted string and that are followed by RFC 5322 comments, allowing trailing comment-separated domain atoms to be retained in the normalized address. For example, the input "user"@example.com(x)evil.com is parsed to the address value 'user@example.com evil.com', which contains additional attacker-controlled domain text separated by a literal space. This parsed value is used without further strict recipient validation when the message envelope is built (envelope.to in src/mime-node), so a malformed/ambiguous recipient address can be accepted and placed in the SMTP envelope. Whether this results in delivery to an unintended recipient on real SMTP servers has not been confirmed. The issue is a variant of the RFC 5322 comment parsing problem addressed in GHSA-cc9r-2j5m-2m83, affecting the separate quoted-local-part code path. Version 10.0.9 contains a fix. | |
| Title | Nodemailer before 10.0.9 Malformed Envelope Recipient via RFC 5322 Comment | |
| First Time appeared |
Nodemailer
Nodemailer nodemailer |
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| Weaknesses | CWE-20 | |
| CPEs | cpe:2.3:a:nodemailer:nodemailer:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Nodemailer
Nodemailer nodemailer |
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| References |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-09-26T13:23:55.786Z
Reserved: 2026-09-26T02:39:50.973Z
Link: CVE-2026-100699
No data.
Status : Received
Published: 2026-09-26T14:16:54.867
Modified: 2026-09-26T14:16:54.867
Link: CVE-2026-100699
No data.
OpenCVE Enrichment
Updated: 2026-09-26T17:00:15Z
Weaknesses