CVE-2025-34400
MailEnable versions prior to 10.54 contain a reflected cross-site scripting (XSS) vulnerability in the AddressesTo parameter of /Mondo/lang/sys/Forms/AddressBook.aspx. The AddressesTo value is not properly sanitized when processed via a GET request and is reflected within a <script> block in the response. By supplying a crafted payload that terminates the existing JavaScript 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.
- No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
ATT&CK techniques
2Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
▤ Build a SIEM detection for these techniquesCAPEC attack patterns
6Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.