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Response snapshot Oct 26, 2026, 22:12 UTC

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VulnerabilityGHSA-85x2-q946-cp5h

Nodemailer: A ">" inside a quoted local part ends an angle-addr early in addressparser, delivering to a domain the header does not name

addressparser ends an angle-addr at the first `>` it sees, including one inside a quoted local part, a comment or a domain literal. The domain is then read off the text in front of that `>`. ` "@good.com>` is the mailbox `"a@evil.com>"@good.

Published Updated

At a glance

Exploited
Not known
Severity
Not scored yet
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: nodemailer: 10.1.4. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-85x2-q946-cp5h (opens a new tab)

What happened

### Vulnerability summary

addressparser ends an angle-addr at the first `>` it sees, including one inside a quoted local part, a comment or a domain literal. The domain is then read off the text in front of that `>`. ` "@good.com>` is the mailbox `"a@evil.com>"@good.com` under RFC 5322, and Nodemailer read it as an address at `evil.com`. The unbracketed spelling of the same value was already read correctly. Affected: 3.0.0 through 10.1.3.

### Attacker capabilities

The attacker controls the text of a recipient or sender address that an application passes to Nodemailer, for example a To value entered in a contact or invite form, or the header of an inbound message parsed with mailparser. No access to the application, its configuration or its credentials is needed. The value is a syntactically valid RFC 5322 address that conformant parsers accept without defects.

Continue reading

### Realistic exploitation scenario

An application lets users send invitations or notifications only to addresses at an allowed domain and validates the submitted value with a conformant parser or by checking its domain. The attacker submits ` "@good.com>`, which validates as a `good.com` mailbox.

Nodemailer then parses the same value, issues `RCPT TO: ` and the message, with whatever content the application puts into it, is delivered to the attacker's domain. The security boundary crossed is the application's recipient allow list. In the inbound direction, mailparser reports a different address than a conformant reader of the same header, so a display or policy layer built on the two disagrees.

### Proof of concept

```js const addressparser = require('nodemailer/lib/addressparser'); console.log(addressparser(" \"@good.com>")); // [ { address: '"a@evil.com', name: '@good.com>' } ] ```

Python's `email._header_value_parser.get_address_list` reads the same value as `"a@evil.com>"@good.com`, with no defects reported.

The envelope a message gets is built from the same parse, so `sendMail({ to: " \"@good.com>" })` issues the RCPT TO shown above.

### Security impact

Mail that an application intends for an allowed domain is delivered to a domain chosen by the attacker, which discloses its content. It is a security vulnerability rather than a parsing bug because the misreading only occurs for values that a conformant validator approves, so validation done the right way is bypassed. Affected are applications that pass user influenced addresses to Nodemailer and consumers of the standalone parser such as mailparser.

The fix tracks quoted strings, comments and domain literals inside an angle-addr and reads only a `>` outside them.

Found in an internal review of addressparser on 2026-10-18. Verified on 3.0.0, 6.9.16 and 10.1.3.

Affected package ranges reported by GitHub: nodemailer: >= 3.0.0, < 10.1.4

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-85x2-q946-cp5h (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-85x2-q946-cp5h, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 23). Nodemailer: A ">" inside a quoted local part ends an angle-addr early in addressparser, delivering to a domain the header does not name. https://kevwire.com/record/GHSA-85x2-q946-cp5h

MLA

"Nodemailer: A ">" inside a quoted local part ends an angle-addr early in addressparser, delivering to a domain the header does not name." KEVWire, 23 Oct. 2026, kevwire.com/record/GHSA-85x2-q946-cp5h.

Chicago

KEVWire. "Nodemailer: A ">" inside a quoted local part ends an angle-addr early in addressparser, delivering to a domain the header does not name." Last modified October 23, 2026. https://kevwire.com/record/GHSA-85x2-q946-cp5h.

Evidence summary (plain text)

Nodemailer: A ">" inside a quoted local part ends an angle-addr early in addressparser, delivering to a domain the header does not name (Oct 23, 2026).
addressparser ends an angle-addr at the first `>` it sees, including one inside a quoted local part, a comment or a domain literal. The domain is then read off the text in front of that `>`. ` "@good.com>` is the mailbox `"a@evil.com>"@good.com` under RFC 5322, and Nodemailer read it as an address at `evil.com`. The unbracketed spelling of the same value was already read correctly. Affected: 3.0.0 through 10.1.3.

The attacker controls the text of a recipient or sender address that an application passes to Nodemailer, for example a To value entered in a contact or invite form, or the header of an inbound message parsed with mailparser. No access to the application, its configuration or its credentials is needed. The value is a syntactically valid RFC 5322 address that conformant parsers accept without defects.
Sources:
GitHub-reviewed advisory GHSA-85x2-q946-cp5h: https://github.com/advisories/GHSA-85x2-q946-cp5h
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: GHSA-85x2-q946-cp5h.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 20:55 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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