RCE in Hsc Cybersecurity Mailinspector
CVE-2026-3610
A vulnerability was found in HSC Cybersecurity Mailinspector up to 5.3.2-3. Affected by this issue is some unknown functionality of the file /mailinspector/mliUserValidation.php of the component URL Handler. The manipulation of the argument error_description results in cross site scripting. The attack may be performed from remote. The exploit has been made public and could be used. Upgrading to version 5.4.0 can resolve this issue. You should upgrade the affected component. The vendor was contacted early and responded very professional: "We have already implemented the fix and made a hotfix available to affected customers, ensuring mitigation while the official release 5.4.0 has not yet been published. This allows customers to address the issue immediately, outside the regular release cycle."
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.005 (38.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 38.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- Hsc Cybersecurity Mailinspector — versions 5.3.2-3, 5.4.0
Weakness classification (CWE)
References
- vuldb.com/ (technical-description, vdb-entry)
- vuldb.com/ (signature, permissions-required)
- vuldb.com/ (third-party-advisory)
- docs.google.com/document/d/1KI2SIDcVm5U3Yzo5tNT5YOwREQWe_5BJaWe-ctRmLoI/edit (exploit, broken-link)
Frequently asked questions
- What is CVE-2026-3610?
- CVE-2026-3610 is a medium-severity vulnerability in Hsc Cybersecurity Mailinspector, classified under Cross-site Scripting. CVSS score: 4.3/10. Published 2026-03-06.
- How severe is CVE-2026-3610?
- Medium severity. CVSS v3 base score is 4.3 out of 10.