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Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

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413,619

Total vulnerabilities in the database

Nodemailer: A ";" inside a quoted string or comment ends an address group early in addressparser, turning display text into a recipient — nodemailer

Improper Input Validation

Vulnerability summary

addressparser ends an RFC 5322 group at the first ;, including one inside a quoted display name or a comment. The text after it is parsed again as top level recipients with the quoting flipped, so text that every conformant parser reads as a display name or comment becomes a live address. G: (a; <[email protected]>) <[email protected]>; names only [email protected], and Nodemailer read it as the single recipient [email protected]. Affected: 3.0.0 through 10.1.3.

Attacker capabilities

The attacker controls the text of an address field that an application passes to Nodemailer, 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 group that conformant parsers accept without defects.

Realistic exploitation scenario

An application validates the recipients of a submitted address list with a conformant parser and only allows addresses at its own domain. The attacker submits G: (a; <[email protected]>) <[email protected]>;. The validator sees one mailbox, [email protected], and approves it. Nodemailer delivers to [email protected] only. The same works through a quoted display name, G: "a;" "<[email protected]>" <[email protected]>;. The boundary crossed is the application's recipient allow list.

Proof of concept

const addressparser = require(&#039;nodemailer/lib/addressparser&#039;);
console.log(addressparser(&quot;G: (a; &lt;[email protected]&gt;) &lt;[email protected]&gt;;&quot;));
// [ { name: &#039;G&#039;, group: [ [Object] ] }, { address: &#039;[email protected]&#039;, name: &#039;) [email protected]&#039; } ]

Python's email._header_value_parser.get_address_list reads the same value as the single mailbox [email protected], with no defects reported.

The envelope a message gets is built from the same parse, so sendMail({ to: "G: (a; <[email protected]>) <[email protected]>;" }) issues the RCPT TO shown above.

Security impact

Mail that an application intends for an approved recipient goes to a recipient chosen by the attacker, which discloses its content, and the intended recipient never receives it. The misreading only occurs on values a conformant validator approves, so correct validation is bypassed, which makes it a security issue rather than a parsing bug. Affected are applications that pass user influenced address lists to Nodemailer and consumers of the standalone parser such as mailparser.

The fix tracks quoted strings and comments inside a group 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.

Published: Oct 23, 2026
Updated: Oct 24, 2026
GHSA: GHSA-m943-m63m-w62w
Severity: Medium
Exploit:
CISA KEV:

CVSS v3:

Severity: Medium
Score: 6.5
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

CWEs:

Affected Software
References

Software	Affected versions
nodemailer	`>= 3.0.0, < 10.1.4`

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.