Progressive Robot hMailServer 6.3.7 Windows Installer privileges management

Summaryinfo

A vulnerability classified as critical has been found in Progressive Robot hMailServer 6.3.7. Affected by this vulnerability is an unknown functionality of the component Windows Installer. This manipulation causes privileges management. This vulnerability is handled as CVE-2026-126625. It is possible to launch the attack on the local host. There is not any exploit available.

Detailsinfo

A vulnerability has been found in Progressive Robot hMailServer 6.3.7 and classified as critical. Affected by this vulnerability is some unknown processing of the component Windows Installer. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Incorrect default permissions in the Windows installer of Progressive Robot hMailServer 6.3.7 allow a local authenticated user to run code as the administrator who installs the product, when it is installed into a new program folder in a location whose permissions let every user write, such as the root of a drive. 6.3.7 fixed CVE-2026-107571 by giving the program folder, Bin and ControlPanel permissions that only administrators may change, but its setup lets Inno Setup make a new program folder first, with the permissions the folder above hands down, and replaces them only afterwards, tens of milliseconds later (33 to 139 milliseconds in the project's test runs). In that time any local account may make files and folders in the new folder, which keep that account as their owner, among them the Bin folder that setup then copies the programs into. Setup runs programs from Bin with the administrator's elevated rights, registering the service among them, before its hardening at the end of setup takes such a folder back, and those programs load a library placed in Bin in place of the system's. The default installation under Program Files, whose folders give ordinary users read and execute only, is not affected.

The advisory is shared at gitlab.com. This vulnerability is known as CVE-2026-126625 since 11/11/2026. The exploitation appears to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Mail Server Software

Vendor

• Progressive Robot

Name

• hMailServer

Version

• 6.3.7

CPE 2.3info

• 🔒

CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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