# CVE-2026-92597 — nodemailer

> As of 2026-09-17, CVE-2026-92597 is a MEDIUM-severity vulnerability in nodemailer, CVSS v3.1 6.5. No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-92597 as of 2026-09-17; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-09-17

## What is CVE-2026-92597?

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.

The record classifies CVE-2026-92597 under weakness class [CWE-436](https://intel.threadlinqs.com/cwe/CWE-436). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 19 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 6.5 — MEDIUM (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N`)
- **CVSS v4.0 base score:** 8.3 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-16, last modified 2026-09-17

## Is CVE-2026-92597 being exploited?

It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **nodemailer**: nodemailer

## How to fix CVE-2026-92597

No vendor patch reference has been recorded for CVE-2026-92597 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-92597

No threat campaign in the Threadlinqs corpus currently references CVE-2026-92597, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org. Last verified by Threadlinqs on 2026-09-17.

**Vendor advisory and patch**

- [github.com — vendor advisory](https://github.com/nodemailer/nodemailer/security/advisories/GHSA-cc9r-2j5m-2m83)
- [github.com — patch](https://github.com/nodemailer/nodemailer/commit/902b63e)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/nodemailer-before-9.1.0-email-domain-validation-bypass-via-rfc-5322-comment)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-92597
Full detection coverage and IOCs for threats exploiting CVE-2026-92597 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp