Nodemailer up to 9.1.0 Content Resolution MailMessage.resolveContent data/key/callback server-side request forgery

Summaryinfo

A vulnerability classified as critical has been found in Nodemailer up to 9.1.0. Impacted is the function MailMessage.resolveContent of the component Content Resolution. This manipulation of the argument data/key/callback causes server-side request forgery. The identification of this vulnerability is CVE-2026-92595. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Nodemailer up to 9.1.0. Affected by this vulnerability is the function MailMessage.resolveContent of the component Content Resolution. The manipulation of the argument data/key/callback with an unknown input leads to a server-side request forgery vulnerability. The CWE definition for the vulnerability is CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Nodemailer (npm package `nodemailer`) versions 9.1.0 and earlier do not honor the `disableFileAccess` and `disableUrlAccess` sandbox options when message content is resolved through the public plugin API `MailMessage.resolveContent()` using the documented legacy three-argument signature `resolveContent(data, key, callback)`. Because `shared.resolveContent()` normalizes the missing `options` argument to an empty object, the message-level flags copied into `mail.data` by the MailMessage constructor are discarded, and `resolveContentValue()` skips both access-control checks, reaching `nmfetch(url)` or `fs.createReadStream(path)`. As a result, plugin or application code that resolves untrusted message content (html, text, attachment `path` or `href`) via this API can be induced to read arbitrary local files or issue outbound HTTP(S) requests (server-side request forgery), bypassing the sandbox the application enabled. The internal paths used by `transporter.sendMail()` (`resolveAll()`, `_convertDataImages()`, and the MIME streaming path) are not affected. Fixed in version 9.1.1.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-92595 since 09/16/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 9.1.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-81295). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Name

• Nodemailer

Version

• 9.0
• 9.1.0

Website

• Product: https://github.com/nodemailer/nodemailer/

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Be aware that VulDB is the high quality source for vulnerability data.

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