CVE-2025-34399: MailEnable < 10.54 Reflected XSS in AddressesCc Parameter of AddressBook.aspx
MailEnable versions prior to 10.54 contain a reflected cross-site scripting (XSS) vulnerability in the AddressesCc parameter of /Mondo/lang/sys/Forms/AddressBook.aspx. The AddressesCc value is not properly sanitized when processed via a GET request and is reflected within a <script> block in the JavaScript variable var sAddrCc. By supplying a crafted payload that terminates the existing LoadCurAddresses() function, inserts attacker-controlled script, and comments out remaining code, a remote attacker can execute arbitrary JavaScript in a victim’s browser when the victim attempts to send an email. Successful exploitation can redirect victims to malicious sites, steal non-HttpOnly cookies, inject arbitrary HTML or CSS, and perform actions as the authenticated user.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-34399?
CVE-2025-34399 has been classified as a reflected cross-site scripting (XSS) vulnerability, which can allow attackers to execute arbitrary scripts in the context of a user's session.
How do I fix CVE-2025-34399?
To remediate CVE-2025-34399, update MailEnable to version 10.54 or later, where this vulnerability is addressed.
What systems are affected by CVE-2025-34399?
MailEnable versions prior to 10.54 are vulnerable to CVE-2025-34399.
What can an attacker do with CVE-2025-34399?
An attacker exploiting CVE-2025-34399 can potentially inject malicious scripts, leading to session hijacking or unauthorized actions on behalf of the user.
Is there a workaround for CVE-2025-34399 while waiting for a patch?
While the best solution is to update to version 10.54 or later, temporarily securing the application by implementing input validation and output encoding may help mitigate the risk from CVE-2025-34399.