Progressive Robot hMailServer up to 6.3.5 live-update live-update apply helper privileges management

Summaryinfo

A vulnerability was found in Progressive Robot hMailServer up to 6.3.5. It has been declared as problematic. Affected by this vulnerability is the function live-update apply helper of the component live-update. Such manipulation leads to privileges management. This vulnerability is documented as CVE-2026-104658. The attack needs to be performed locally. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Progressive Robot hMailServer up to 6.3.5. Affected by this issue is the function live-update apply helper of the component live-update. The manipulation with an unknown input leads to a privileges management vulnerability. Using CWE to declare the problem leads to CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Impacted is confidentiality, integrity, and availability. CVE summarizes:

The Linux live-update apply helper (hmailserver-update) of Progressive Robot hMailServer 6.3.4 and 6.3.5 runs as root on a request file written by the unprivileged hmailserver service account, and took from that request the program used to verify an AppImage update's signature and the systemd unit to stop before reading the service account's files. An attacker who already runs code as the hmailserver service account, for example through another flaw in the mail server, can therefore have arbitrary code executed as root, on any Linux installation where the live update's path unit is active - the default for the project's .deb and .rpm packages - and on AppImage installations run under that unit.

The advisory is shared for download at gitlab.com. This vulnerability is handled as CVE-2026-104658 since 10/02/2026. The exploitation is known to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 6.3.6 eliminates this vulnerability.

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Productinfo

Type

• Mail Server Software

Vendor

• Progressive Robot

Name

• hMailServer

Version

• 6.3.0
• 6.3.1
• 6.3.2
• 6.3.3
• 6.3.4
• 6.3.5

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

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• 🔒
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Once again VulDB remains the best source for vulnerability data.

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