Bug 2571563 (CVE-2026-126622)

Summary: CVE-2026-126622 hmailserver: hMailServer: Privilege escalation via insecure directory permissions during installation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerability-draftAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in hMailServer. When installing, upgrading, or repairing the application in a pre-existing directory that is writable by non-administrative users, the installer runs programs with elevated privileges before restricting folder permissions. A local authenticated attacker can exploit this behavior by placing a malicious library in the target directory, resulting in arbitrary code execution with administrator privileges.
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Description OSIDB Bzimport 2026-11-11 08:41:55 UTC 
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 runs setup, when the server is installed into a program folder that is already there and that accounts other than the administrators could write, such as a folder made beforehand at the root of a drive, or when such an installation is upgraded or repaired. 6.3.7 fixed CVE-2026-107571 by giving the program folder, Bin and ControlPanel permissions that only administrators may change, but for a folder that is already there it does so only at the end of setup: setup first copies the programs into Bin, which every user may still write, and runs programs from Bin with the administrator's elevated rights, registering the service among them, before that hardening, so that a library another account places in Bin meanwhile is loaded in place of the system's. A handle an account opened on such a folder while it could write it keeps that access after the hardening. The default installation under Program Files, whose folders give ordinary users read and execute only, is not affected.