mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the user dashboard's "Seen successful connections" (login history) renders the client IP from login logs without HTML escaping. Because the server trusts the X-Real-IP header as the source IP for logging, an attacker can inject HTML/JS into this field. This Self-XSS can be exploited by a Login CSRF to force the victim into the attacker's account, and then read emails in a previous browser tab. Version 2026-03b fixes the vulnerability.

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the admin dashboard's Autodiscover logs render the EMailAddress value (logged as the "user" field) without HTML escaping. By submitting an unauthenticated Autodiscover request with a crafted EMailAddress containing HTML/JS, the payload is stored in Redis and executed when an admin views the Autodiscover logs. Version 2026-03b fixes the vulnerability.

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the mailcow web interface passes the raw `$_SERVER['REQUEST_URI']` to Twig as a global template variable and renders it inside a JavaScript string literal in the `setLang()` helper of `base.twig`, relying on Twig's default HTML auto-escaping instead of the context-appropriate `js` escaping strategy. In addition, the `query_string()` Twig helper merges all current `$_GET` parameters into the language-switching links on the login page, so attacker-supplied parameters are reflected and preserved across navigation. Version 2026-03b fixes the vulnerability.

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the Quarantine details modal injects attachment filenames into HTML without escaping, allowing arbitrary HTML/JS execution. An attacker can deliver an email with a crafted attachment name so that when an admin views the quarantine item, JavaScript executes in their browser, taking over their account. Version 2026-03b fixes the vulnerability.

mailcow: dockerized is an open source groupware/email suite based on docker. An authenticated admin user can inject a JavaScript payload into the Relay Hosts configuration. The injected payload is executed whenever the configuration page is viewed, enabling the attacker to execute arbitrary scripts in the context of the user's browser. This could lead to data theft, or further exploitation. This issue has been addressed in the `2024-07` release. All users are advised to upgrade. There are no known workarounds for this vulnerability.

mailcow: dockerized is an open source groupware/email suite based on docker. An unauthenticated attacker can inject a JavaScript payload into the API logs. This payload is executed whenever the API logs page is viewed, potentially allowing an attacker to run malicious scripts in the context of the user's browser. This could lead to unauthorized actions, data theft, or further exploitation of the affected system. This issue has been addressed in the `2024-07` release. All users are advised to upgrade. There are no known workarounds for this vulnerability.

mailcow: dockerized is an open source groupware/email suite based on docker. A security vulnerability has been identified in mailcow affecting versions prior to 2024-04. This vulnerability resides in the exception handling mechanism, specifically when not operating in DEV_MODE. The system saves exception details into a session array without proper sanitization or encoding. These details are later rendered into HTML and executed in a JavaScript block within the user's browser, without adequate escaping of HTML entities. This flaw allows for Cross-Site Scripting (XSS) attacks, where attackers can inject malicious scripts into the admin panel by triggering exceptions with controlled input. The exploitation method involves using any function that might throw an exception with user-controllable argument. This issue can lead to session hijacking and unauthorized administrative actions, posing a significant security risk. Version 2024-04 contains a fix for the issue.

Mailcow: dockerized is an open source groupware/email suite based on docker. A Cross-Site Scripting (XSS) vulnerability has been identified within the Quarantine UI of the system. This vulnerability poses a significant threat to administrators who utilize the Quarantine feature. An attacker can send a carefully crafted email containing malicious JavaScript code. This issue has been patched in version 2023-11.