---
title: "CVE-2026-104658: Progressive Robot hMailServer - Privilege Escalation"
description: "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."
url: https://panop.io/threat-heartbeat/CVE-2026-104658/
---

# 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 ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-104658)

## 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](https://cwe.mitre.org/data/definitions/807.html)

## 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

- [https://nvd.nist.gov/vuln/detail/CVE-2026-104658](https://nvd.nist.gov/vuln/detail/CVE-2026-104658)
- [https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6](https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6)
- [https://gitlab.com/hmailserver/hmailserver/-/work\_items/58](https://gitlab.com/hmailserver/hmailserver/-/work_items/58)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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