CVE-2025-34402

MEDIUM
Published Dec 9, 2025 Modified Dec 9, 2025 CWE-79

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.

CVSS v3.1 Score

6.1
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor Product
mailenable mailenable

References

Frequently Asked Questions

What is CVE-2025-34402? +
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. It has a CVSS v3.1 base score of 6.1 (MEDIUM).
How severe is CVE-2025-34402? +
CVE-2025-34402 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2025-34402? +
CVE-2025-34402 affects products from mailenable, specifically: mailenable. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-34402? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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