---
id: "CVE-2026-114489"
kind: "vulnerability"
aliases: ["CVE-2026-114489"]
title: "hMailServer: domain-confined admins can reroute mail across tenants"
severity: "high"
cvss: 8.1
epss: 0.00272
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["hmailserver", "mail-server", "multi-tenant", "package", "self-hosted"]
not_affected_if: ["no-domain-scoped-credentials", "single-tenant"]
published_at: "2026-10-21T16:17:35+00:00"
first_seen_at: "2026-10-23T21:57:29+00:00"
updated_at: "2026-10-25T03:05:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114489", "first_seen_at": "2026-10-23T21:57:29+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114489", "first_seen_at": "2026-10-24T13:15:54+00:00"}]
---

# hMailServer: domain-confined admins can reroute mail across tenants

Progressive Robot hMailServer 6.0.0 through 6.3.6 fails to check authorization on its REST and COM administration APIs, so a credential limited to certain domains can change mail routing and domain settings for other domains. An attacker in a shared multi-tenant server can create aliases that divert other tenants' mail to their own address, rename domains, or point relay and rule actions at the server's internal addresses and stored route credentials.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- Upgrade hMailServer past 6.3.6 once a fixed release is published; check the vendor page for the exact version.
- Until patched, restrict administrative API and COM access to trusted administrators and review domain aliases and relay hosts for unexpected entries.

## Timeline

- 2026-10-23T21:57:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114489
- 2026-10-24T13:15:54+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114489

## From the sources

Missing authorization in the REST and COM administration APIs of Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote authenticated user whose credential is confined to named domains to change mail routing and domain configuration beyond those domains on a multi-tenant server. A domain administrator, an account or API key given another role that manages accounts in named domains, or a full-scope API key issued for named domains could create a domain alias for any name (so that other tenants' mail for that name is diverted to an address the attacker controls, or denied), rename a domain to any name the server does not host, set a rule's bind-to-address, send-using-route or script-function action to reach one of the server's own addresses, a configured route's stored credentials or a function of the server's event script, and set the domain's relay host - which delivery then connects to with no address rule - to an address on the server's own network; and over the COM API any account could set the three rule actions on its own rules, where the script-function action runs at delivery. The authorization gate did not refuse these routes to a confined credential and the handlers were not given the caller; over COM the domain-alias save performed no authorization check at all, the domain rename required only a domain administrator, and a rule save required at most that the caller could change the rule's owner.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_