Node nodemailer: Nodemailer versions >= 6.9.16 and < 9.1.0 mis-parse RFC 5322 comments in email addresses: in
Affects node-nodemailerSource GCVE Database
Not known to be exploited · CVSS 6.5 Medium · fixed in 9.1.0 : update node-nodemailer when convenient.
Data as of 28 Oct 2026, 22:28 UTC
- Patch
- Available – fixed in 9.1.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 16 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10node-nodemailerpkg:deb/ubuntu/node-nodemailer?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSnode-nodemailerpkg:deb/ubuntu/node-nodemailer?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSnode-nodemailerpkg:deb/ubuntu/node-nodemailer?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSnode-nodemailerpkg:deb/ubuntu/node-nodemailer?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSnode-nodemailerpkg:deb/ubuntu/node-nodemailer?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
Nodemailer versions >= 6.9.16 and < 9.1.0 mis-parse RFC 5322 comments in email addresses: in lib/addressparser, a comment closed immediately before a non-break character causes the tokenizer to concatenate the atoms surrounding the comment instead of treating the comment as folding whitespace that terminates the domain. A recipient address such as user@good-corp.com(x)evil.com is therefore read by Nodemailer as the single domain good-corp.comevil.com (registrable domain comevil.com, which an attacker can register) and used for both the SMTP envelope (RCPT TO) and the emitted To:/From: headers, while a conformant RFC 5322 parser terminates the domain at the comment and reads good-corp.com. An application that validates the recipient domain with a strict RFC 5322 parser (without inspecting parse defects) or a naive prefix/substring allow-list and then hands the raw address to Nodemailer can be induced to deliver mail to a domain the attacker controls. Fixed in 9.1.0.