# CVE-2026-82853: Nodemailer SMTP command injection via CRLF in transport name

Source: https://junglewise.ai/threats/cve-2026-82853-nodemailer-smtp-command-injection-via-crlf-in-transport-name  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-31. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-82853 · Severity: medium · CVSS 4.9 · Published 2026-08-31

Nodemailer is a popular Node.js library for sending emails via SMTP. A flaw in versions up to 8.0.4 allows attackers who can control the transport name configuration option to inject arbitrary SMTP commands by embedding carriage-return and line-feed characters. This could enable phishing attacks, email spoofing, and unauthorized message relaying through the target's SMTP server.

Technologies: [Nodemailer](https://junglewise.ai/threats/technologies/nodemailer). Vendors: [Nodemailer](https://junglewise.ai/threats/vendors/nodemailer).

## Quick answers

**Is CVE-2026-82853 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-82853 being exploited in the wild.

**How severe is CVE-2026-82853?** Medium severity, with a CVSS score of 4.9, published 31 August 2026.

**Which products and versions are affected?** Nodemailer up to and including 8.0.4.

**Is there a fix for CVE-2026-82853?** A patch was published on 2026-04-08: Fix released in version 8.0.5 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-82853 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-82853?** Check whether you run Nodemailer at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a CRLF injection in the SMTP connection initialization code (lib/smtp-connection/index.js). The transport name option is concatenated directly into the EHLO/HELO/LHLO SMTP commands without sanitization for \r\n sequences. When the SMTP server processes these injected newlines, each becomes a separate command; an attacker can inject MAIL FROM, RCPT TO, DATA, and email content to send fraudulent messages. The attack occurs before authentication and requires only the ability to control the name configuration parameter—for example, in multi-tenant SaaS platforms, admin panels with database-driven SMTP settings, or applications accepting external configuration. A fix is available in version 8.0.5, which strips CRLF characters from the name parameter.

## Affected products

- Nodemailer Nodemailer up to and including 8.0.4

## Identifiers

- CVE-2026-82853
- GHSA-vvjj-xcjg-gr5g

## Timeline

- 2026-04-08: disclosed: GHSA-vvjj-xcjg-gr5g published
- 2026-04-08: patched: Fix released in version 8.0.5

## References

- [https://github.com/nodemailer/nodemailer/security/advisories/GHSA-vvjj-xcjg-gr5g](https://github.com/nodemailer/nodemailer/security/advisories/GHSA-vvjj-xcjg-gr5g)
- [https://github.com/nodemailer/nodemailer/commit/0a43876801a420ca528f492eaa01bfc421cc306e](https://github.com/nodemailer/nodemailer/commit/0a43876801a420ca528f492eaa01bfc421cc306e)

## Related threats

- [Nodemailer address parsing bypass in addressparser](https://junglewise.ai/threats/cve-2026-125755-nodemailer-3-0-0-before-10-4-1-contains-an-address-parsing-flaw)
- [Nodemailer address parsing bypass in nested RFC 5322 comments](https://junglewise.ai/threats/cve-2026-121424-nodemailer-from-3-0-0-before-10-1-4-contains-an-address-parsing)
- [Nodemailer addressparser RFC 5322 comment parsing bypass](https://junglewise.ai/threats/nodemailer-a-nested-comment-ends-early-in-addressparser-releasing-the-4e80613c)
- [Nodemailer addressparser group terminator bypass in quoted strings](https://junglewise.ai/threats/nodemailer-a-inside-a-quoted-string-or-comment-ends-an-address-group-b8b045f9)
- [Nodemailer addressparser angle-addr parsing bypass](https://junglewise.ai/threats/nodemailer-a-inside-a-quoted-local-part-ends-an-angle-addr-early-in-28663cfb)