CVE-2025-34402 MailEnable < 10.54 Reflected XSS in FieldCc Parameter of AddressBook.aspx

Medium 5.3 Published Updated

Remote attackers can execute arbitrary JavaScript in victims' browsers via a reflected XSS vulnerability in the MailEnable AddressBook interface.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
A user has to click or open something
Fix
None listed

What is CVE-2025-34402?

CVE-2025-34402 is a medium-severity cross-site scripting vulnerability in Mailenable Mailenable, published on 9 Dec 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

MailEnable versions prior to 10.54 contain a reflected cross-site scripting (XSS) vulnerability in the FieldCc parameter of /Mondo/lang/sys/Forms/AddressBook.aspx. The FieldCc value is not properly sanitized when processed via a GET request and is reflected inside a <script> block in the JavaScript variable var CCFieldProvided. 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.

Weakness: CWE-79

Which versions are affected by CVE-2025-34402?

It affects 1 product.

Products include Mailenable Mailenable.

How do I fix CVE-2025-34402?

No fix has been published for CVE-2025-34402 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-34402 being exploited?

There is no known exploitation of CVE-2025-34402 in the wild and no public exploit code.

All Mailenable Mailenable vulnerabilities

Sources

Also known as GHSA-hcm9-8qqf-jc2f.

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