CVE-2026-90776 - Vulnerability Details

- Nodemailer 9.1.0 through 10.0.4 Denial of Service via Quadratic Address Parsing

Description

Nodemailer versions 9.1.0 through 10.0.4 contain a quadratic time complexity vulnerability in the addressparser component when parsing email addresses with RFC 5322 comments. Attackers can craft malicious email headers with comment-separated atoms to consume excessive CPU and block the Node.js event loop for several seconds, causing denial of service.

Published: 2026-09-13

Score: 8.7 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

Nodemailer versions 9.1. a quadratic time‑complexity bug in the addressparser component. When parsing email headers that include RFC 5322 comments, the algorithm performs excessive computation (CWE‑407), consuming large amounts of CPU and temporarily blocking the Node.js event loop. This results in a denial‑of‑service condition for applications that rely on Nodemailer to send or parse mail.

Affected Systems

The vulnerability affects the Nodemailer library distributed via npm. Any deployment that uses Nodemailer versions 9.1.0, 9.2.x, 9.3.x, 10.0.4 is impacted; upgrading flaw.

Risk and Exploitability

The CVSS score of 8.7 classifies this vulnerability as high severity, while the EPSS score of < 1% indicates a very low probability of exploitation; it is not listed in CISA KEV. An attacker can exploit the weakness simply by sending a crafted email containing comment‑separated atoms to a system that parses addresses with Nodemailer. The attack can block the event loop for several seconds, disrupting service availability.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

nodemailer

unaffected

Version	Status	Constraints
`9.1.0`	affected	< 10.0.5
`10.0.5`	unaffected	—

No data.

Vendor Product Confidence Versions

Nodemailer

90%

Version	Status	Scheme	Platform
`[9.1.0,10.0.5)`	affected	semver	—
`10.0.5`	unaffected	semver	—

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Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Nodemailer to version 10.0.5 or newer.
If an upgrade cannot be performed immediately, implement input validation to limit comment length or sanitize incoming email headers before parsing.
Monitor CPU utilization and logs for abnormal spikes that indicate address parsing loops, and block or rate‑limit suspicious traffic.

Generated by OpenCVE AI on September 15, 2026 at 17:53 UTC.

Tracking

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Advisories

No advisories yet.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00684.

Exploitation poc

Automatable yes

Technical Impact partial

References

Link	Providers
https://github.com/nodemailer/nodemailer
https://github.com/nodemailer/nodemailer/blob/v10.0.4/src/addressparser/index.ts#L251
https://github.com/nodemailer/nodemailer/commit/c07f17518d25aca8ab2ad66968dcbca538c24b89
https://github.com/nodemailer/nodemailer/releases/tag/v10.0.5
https://github.com/nodemailer/nodemailer/security/advisories/GHSA-prgh-xp8r-p3m5
https://nvd.nist.gov/vuln/detail/CVE-2026-90776
https://www.cve.org/CVERecord?id=CVE-2026-90776
https://www.vulncheck.com/advisories/nodemailer-9.1.0-through-10.0.4-denial-of-service-via-quadratic-address-parsing

History

Wed, 16 Sep 2026 14:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Mon, 14 Sep 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-1333
References		https://nvd.nist.gov/vuln/detail/CVE-2026-90776 https://www.cve.org/CVERecord?id=CVE-2026-90776
Metrics	threat_severity `None`	threat_severity `Important`

Sun, 13 Sep 2026 11:45:00 +0000

Type	Values Removed	Values Added
Description		Nodemailer versions 9.1.0 through 10.0.4 contain a quadratic time complexity vulnerability in the addressparser component when parsing email addresses with RFC 5322 comments. Attackers can craft malicious email headers with comment-separated atoms to consume excessive CPU and block the Node.js event loop for several seconds, causing denial of service.
Title		Nodemailer 9.1.0 through 10.0.4 Denial of Service via Quadratic Address Parsing
First Time appeared		Nodemailer Nodemailer nodemailer
Weaknesses		CWE-407
CPEs		cpe:2.3:a:nodemailer:nodemailer::::::::
Vendors & Products		Nodemailer Nodemailer nodemailer
References		https://github.com/nodemailer/nodemailer https://github.com/nodemailer/nodemailer/blob/v10.0.4/src/addressparser/index.ts#L251 https://github.com/nodemailer/nodemailer/commit/c07f17518d25aca8ab2ad66968dcbca538c24b89 https://github.com/nodemailer/nodemailer/releases/tag/v10.0.5 https://github.com/nodemailer/nodemailer/security/advisories/GHSA-prgh-xp8r-p3m5 https://www.vulncheck.com/advisories/nodemailer-9.1.0-through-10.0.4-denial-of-service-via-quadratic-address-parsing
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}` cvssV4_0 `{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}`

Subscriptions

Nodemailer Nodemailer

MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-09-13T11:42:26.391Z

Updated: 2026-09-24T14:21:56.169Z

Reserved: 2026-09-13T11:15:41.904Z

Link: CVE-2026-90776

Vulnrichment

Updated: 2026-09-16T14:04:45.962Z

NVD

Status : Awaiting Analysis

Published: 2026-09-13T12:17:16.547

Modified: 2026-09-24T20:47:31.797

Link: CVE-2026-90776

Redhat

Severity : Important

Publid Date: 2026-09-13T11:42:26Z

Links: CVE-2026-90776 - Bugzilla

OpenCVE Enrichment

Updated: 2026-09-15T18:00:17Z

Weaknesses

CWE-1333
Inefficient Regular Expression Complexity
CWE-407
Inefficient Algorithmic Complexity

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Exploitation poc

Automatable yes

Technical Impact partial

Subscriptions

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