TYPO3-EXT-SA-2026-037: Multiple vulnerabilities in extension "Mail" (mail)

• Release Date: November 3, 2026
• Component Type: Third party extension. This extension is not a part of the TYPO3 default installation.
• Component: "Mail" (mail)
• Composer Package Name: mediaessenz/mail
• Vulnerability Type: Open Redirection, Information Disclosure, Broken Access Control, Server-Side Request Forgery, Cross-Site Scripting
• Affected Versions: 3.12.4 and below, 4.0.0 - 4.1.0
• Severity: High
• Suggested CVSS: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
• References: CVE-2026-120327, CVE-2026-120328, CVE-2026-120329, CVE-2026-120330, CVE-2026-120331, CVE-2026-120332, CWE-601, CWE-639, CWE-74, CWE-862, CWE-918, CWE-79

Problem Description

The click tracking middleware accepts an arbitrary target URL and redirects to it. Attackers can misuse links to the website to redirect users to external sites. (CVE-2026-120327)

The click tracking middleware does not validate the authentication code of a recipient if the code is omitted. Unauthenticated attackers can retrieve personal data of newsletter recipients, which is inserted into links of sent mails. (CVE-2026-120328)

Saving the configuration of the mail backend module writes submitted settings to the page TSconfig without restricting them to the configuration options of the module. Backend users with access to the mail module can write arbitrary page TSconfig. (CVE-2026-120329)

Backend actions and ajax routes of the mail module do not check whether the backend user has access to the page of the requested mail or recipient group. Backend users with access to the mail module can view, change, send and export mails and recipient groups outside their web mounts, including the personal data of recipients. (CVE-2026-120330)

Content of external URL mails, their stylesheets and images to embed is fetched by the server without validating the target host. Backend users with access to the mail module can make the server send requests to hosts in the internal network. (CVE-2026-120331)

The HTML content of mails and tracked URLs are rendered unescaped in the backend module. Backend users with access to the mail module can inject arbitrary HTML and JavaScript, which is executed in the context of other backend users viewing the mail preview or report. (CVE-2026-120332)

Solution

Updated versions 3.12.5 and 4.2.0 are available from the TYPO3 extension manager, packagist and at

https://extensions.typo3.org/extension/download/mail/3.12.5/zip
https://extensions.typo3.org/extension/download/mail/4.2.0/zip

Users of the extension are advised to update the extension as soon as possible.

Credits

Thanks to Alexander Grein for reporting the vulnerabilities and for providing updated versions of the extension.

General Advice

Follow the recommendations that are given in the TYPO3 Security Guide.