XSS in Mailenable

CVE-2025-34425

MailEnable versions prior to 10.54 contain a reflected cross-site scripting (XSS) vulnerability in the WindowContext parameter of /Mondo/lang/sys/Forms/MAI/compose.aspx. The WindowContext value is not properly sanitized when processed via a GET request and is reflected within a <script> context in the JavaScript variable window.location, allowing an attacker to break out of the existing script and inject arbitrary JavaScript. A remote attacker can supply a crafted payload that terminates the existing ProcessContextSwitchResult() function, inserts attacker-controlled script, and comments out remaining code, leading to script execution in a victim’s browser when the victim visits a malicious link or 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.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.004 (27.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-34425?
CVE-2025-34425 is a medium-severity vulnerability in Mailenable, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2025-12-09.
How severe is CVE-2025-34425?
Medium severity. CVSS v3 base score is 6.1 out of 10.