CVE-2026-104658 Progressive Robot hMailServer - Privilege Escalation

Progressive Robot hMailServer 6.3.4 and 6.3.5 contain a privilege escalation caused by the live-update apply helper running as root and executing attacker-controlled files from the unprivileged service account, letting attackers with service account code execution escalate to root, exploit requires prior code execution as hmailserver service account.

CVSS base score 7.8 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.11% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Privilege Escalation
Impact
Privilege Escalation
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
8 October 2026
Updated
15 October 2026
Weakness
CWE-807

Vendor fix

Update to a version later than 6.3.5 or apply vendor patches addressing the live-update helper privilege escalation.

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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