Summary
Nodemailer: A ">" inside a quoted local part ends an angle-addr early in addressparser, delivering to a domain the header does not name
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 >. <"[email protected]>"@good.com> is the mailbox "[email protected]>"@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.
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 <"[email protected]>"@good.com>, which validates as a good.com mailbox. Nodemailer then parses the same value, issues RCPT TO:<"\"a"@evil.com> 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
const addressparser = require('nodemailer/lib/addressparser');
console.log(addressparser("<\"[email protected]>\"@good.com>"));
// [ { address: '"[email protected]', name: '@good.com>' } ]
Python's email._header_value_parser.get_address_list reads the same value as "[email protected]>"@good.com, with no defects reported.
The envelope a message gets is built from the same parse, so sendMail({ to: "<\"[email protected]>\"@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.
Impact
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
GHSA-85X2-Q946-CP5H has a CVSS score of 6.5 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (10.1.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is GHSA-85X2-Q946-CP5H? GHSA-85X2-Q946-CP5H is a medium-severity improper input validation vulnerability in nodemailer (npm), affecting versions >= 3.0.0, < 10.1.4. It is fixed in 10.1.4. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- How severe is GHSA-85X2-Q946-CP5H? GHSA-85X2-Q946-CP5H has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of nodemailer are affected by GHSA-85X2-Q946-CP5H? nodemailer (npm) versions >= 3.0.0, < 10.1.4 is affected.
- Is there a fix for GHSA-85X2-Q946-CP5H? Yes. GHSA-85X2-Q946-CP5H is fixed in 10.1.4. Upgrade to this version or later.
- Is GHSA-85X2-Q946-CP5H exploitable, and should I be worried? Whether GHSA-85X2-Q946-CP5H is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-85X2-Q946-CP5H is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-85X2-Q946-CP5H? Upgrade
nodemailerto 10.1.4 or later.