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 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.
CVE-2025-34398
MEDIUMNVD 6.16.1—
EchelonGraph scoreMEDIUM confidence
Score 6.1 from GitHub Security Advisory published 2025-12-09. NVD baseline CVSS 6.1; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.1Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.1
- EG Score
- 6.1(medium)
- EG Risk
- 43(Track)EG Risk 43/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity61% × 45%Exploitation0% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 33%
- KEV
- Not listed
Published
December 9, 2025
Last Modified
December 9, 2025
References (3)
- disclosure@vulncheckhttps://mailenable.com/Standard-ReleaseNotes.txt
- disclosure@vulncheckhttps://www.mailenable.com/
- disclosure@vulncheckhttps://www.vulncheck.com/advisories/mailenable-reflected-xss-in-addressesbcc-parameter-of-addressbook-aspx
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Frequently asked(5)
What is CVE-2025-34398?
CVE-2025-34398 is a medium vulnerability published on December 9, 2025. 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…
When was CVE-2025-34398 disclosed?
CVE-2025-34398 was first published in the National Vulnerability Database on December 9, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-34398 actively exploited?
CVE-2025-34398 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 66.6% of all scored CVEs.
What is the CVSS score of CVE-2025-34398?
CVE-2025-34398 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2025-34398?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-34398, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
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