CVE-2026-3610 HSC Cybersecurity Mailinspector URL mliUserValidation.php cross site scripting
Remote attackers can execute arbitrary scripts via the error_description parameter in Mailinspector, potentially leading to session hijacking or code execution.
- 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-2026-3610?
CVE-2026-3610 is a medium-severity cross-site scripting vulnerability in HSC Cybersecurity Mailinspector, published on 6 Mar 2026. 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
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."
Which versions are affected by CVE-2026-3610?
How do I fix CVE-2026-3610?
No fix has been published for CVE-2026-3610 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-2026-3610 being exploited?
There is no known exploitation of CVE-2026-3610 in the wild and no public exploit code.
Sources
Also known as GHSA-rgc7-cqpm-cvh8.