How severe is CVE-2025-34398?

CVE-2025-34398 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2025-34398 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-34398?

CVE-2025-34398 affects Mailenable. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-34398?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-34398 have an EU (EUVD) identifier?

Yes. CVE-2025-34398 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-202186.

When was CVE-2025-34398 published?

CVE-2025-34398 was published on 2025-12-09 and last updated on 2026-06-17.

CVE-2025-34398

CVE-2025-34398 is a medium-severity vulnerability in Mailenable with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 5.3
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-202186
Weakness: CWE-79
Affected product: Mailenable
Published: 2025-12-09
Last modified: 2026-06-17

Description

MailEnable versions prior to 10.54 contain a reflected cross-site scripting (XSS) vulnerability in the AddressesBcc parameter of /Mondo/lang/sys/Forms/AddressBook.aspx. The AddressesBcc value is not properly sanitized when processed via a GET request and is reflected within a <script> block in the JavaScript variable var sAddrBcc. 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, and perform actions as the authenticated user.

Frequently asked questions

What is CVE-2025-34398?: MailEnable versions prior to 10.54 contain a reflected cross-site scripting (XSS) vulnerability in the AddressesBcc parameter of /Mondo/lang/sys/Forms/AddressBook.aspx. The AddressesBcc value is not properly sanitized when processed via a GET request and is reflected within a <script> block in the JavaScript variable var sAddrBcc. 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, and perform actions as the authenticated user.
How severe is CVE-2025-34398?: CVE-2025-34398 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-34398 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-34398?: CVE-2025-34398 affects Mailenable. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-34398?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-34398 have an EU (EUVD) identifier?: Yes. CVE-2025-34398 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-202186.
When was CVE-2025-34398 published?: CVE-2025-34398 was published on 2025-12-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mailenable:mailenable:*:*:*:*:standard:*:*:*

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