CVE-2026-100741 Progressive Robot Ltd hMailServer - Command Injection

Progressive Robot Ltd hMailServer 6.0.0 through 6.3.3 on Windows contains a command injection caused by improper escaping of backslash in JScript event-script dispatcher, letting remote unauthenticated attackers execute arbitrary JScript with service account privileges, exploit requires event scripting enabled, JScript language, and specific event handlers defined.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
1.73% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Command Injection
Impact
Remote Code Execution
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
27 September 2026
Updated
15 October 2026
Weakness
CWE-95

Vendor fix

Update to a version later than 6.3.3 or apply patches that fix event script injection.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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