Vulnerability · Published Oct 8, 2026 · Assigned by GitLab
CVE-2026-104658Reliance on Untrusted Inputs in a Security Decision in hMailServer
High 7.8
In plain English
A high-severity security flaw in hMailServer from Progressive Robot Ltd. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Progressive Robot Ltd | hMailServer | 6.3.4 – before 6.3.6 |
Weakness: CWE-807 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H