wneessen go-mail up to 0.7.0 MAIL FROM/RCPT TO argument injection

Summaryinfo

A vulnerability, which was classified as critical, was found in wneessen go-mail up to 0.7.0. This affects an unknown function. Executing a manipulation of the argument MAIL FROM/RCPT TO can lead to argument injection. This vulnerability is handled as CVE-2025-59937. The attack can be executed remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in wneessen go-mail up to 0.7.0. It has been declared as critical. This vulnerability affects some unknown functionality. The manipulation of the argument MAIL FROM/RCPT TO with an unknown input leads to a argument injection vulnerability. The CWE definition for the vulnerability is CWE-88. The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

go-mail is a comprehensive library for sending mails with Go. In versions 0.7.0 and below, due to incorrect handling of the mail.Address values when a sender- or recipient address is passed to the corresponding MAIL FROM or RCPT TO commands of the SMTP client, there is a possibility of wrong address routing or even ESMTP parameter smuggling. For successful exploitation, it is required that the user's code allows for arbitrary mail address input (i. e. through a web form or similar). If only static mail addresses are used (i. e. in a config file) and the mail addresses in use do not consist of quoted local parts, this should not affect users. This issue is fixed in version 0.7.1

The advisory is shared for download at github.com. This vulnerability was named CVE-2025-59937 since 09/23/2025. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.

Upgrading to version 0.7.1 eliminates this vulnerability. Applying the patch 42e92cfe027be04aff72921adb0f72f11d517479 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• wneessen

Name

• go-mail

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7.0

License

• open-source

Website

• Product: https://github.com/wneessen/go-mail/

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