Progressive Robot hMailServer up to 6.3.5 Administrative Command-Line Operations hMailServer.exe path traversal

Summaryinfo

A vulnerability, which was classified as critical, has been found in Progressive Robot hMailServer up to 6.3.5. Affected by this issue is some unknown functionality of the file hMailServer.exe of the component Administrative Command-Line Operations. This manipulation causes path traversal. The identification of this vulnerability is CVE-2026-107578. The attack can only be executed locally. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Progressive Robot hMailServer up to 6.3.5. It has been declared as critical. Affected by this vulnerability is an unknown functionality of the file hMailServer.exe of the component Administrative Command-Line Operations. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Improper link resolution and external control of file paths in the administrative command-line operations of hMailServer.exe in Progressive Robot hMailServer 6.3.4 and 6.3.5 allow a local attacker who already runs code as the low-privilege service account to escalate privilege. On Windows, operations run with administrator rights by the installer, DBSetup, the Control Panel or an administrator wrote log entries and crash records into the log folder, created, deleted and changed the permissions of the self-signed certificate and private key in the data folder, and rewrote message files in the data folder, all by path in folders the service account (NT SERVICE\hMailServer, the default for new installations since 6.3.4) can modify, following junctions and mount points; and the store-maintenance operations reached files by names taken from the database, which the service account can write, including names outside the data folder. On Linux, the store-maintenance and object-storage operations run as root followed symbolic links the service account (the packaged hmailserver user, which owns the data folder) planted in it, so a root-run operation read, wrote or removed the link's target as root. A local attacker controlling the service account can thereby gain the administrator's (Windows) or root's (Linux) privileges when such an operation is run.

It is possible to read the advisory at gitlab.com. This vulnerability is known as CVE-2026-107578 since 10/08/2026. The exploitation appears to be easy. Attacking locally is a requirement. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

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

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CPE 2.2info

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