CVE-2026-114475: Missing Authorization in hMailServer

Published Oct 21, 2026
·
Updated

Missing authorization in the REST role-management routes of Progressive Robot hMailServer 6.3.4 through 6.3.6 allows a remote authenticated user whose credential is confined to named domains to modify a custom role that accounts in other domains hold, and to create custom roles and delete any that no account holds. The routes that create, update and delete a custom role require the manageroles permission, which only the serveradmin role holds; but a full-scope API key issued for named domains, and serveradmin assigned with a domain list, are serveradmin confined to those domains and hold manageroles. The server's authorization gate did not refuse the three role routes to a confined credential and the route named no domain, so a credential issued to one tenant could raise or lower the permissions of a custom role assigned across other tenants - granting another domain's role every permission over its mailboxes and settings, or removing what it needs. A custom role may not hold administerserver, administerdomain or manageroles, so the confined credential cannot make itself or another a server administrator by creating or rewriting a custom role.

Affected Software

1 affected component
Progressive Robot hMailServer>=6.3.4<=6.3.6

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Progressive Robot hMailServer to a version that resolves this vulnerability.

    Fixed in 6.3.7
  2. Configuration

    Keep the REST API disabled by setting RestApiPort=0 where it is not needed.

    hMailServer REST API RestApiPort = 0
  3. Compensating control

    On multi-tenant servers, do not issue a full-scope API key or assign the serveradmin role confined to named domains to a party that is not trusted with the whole server.

  4. Operational

    Review custom roles' permissions for changes that a confined credential should not have made, including after upgrading because the upgrade does not undo prior changes.

Event History

Oct 21, 2026
CVE Published
via MITRE·03:12 PM
Data Sourced
via MITRE·03:12 PM
RemedyDescriptionSeverityWeakness

Frequently Asked Questions

1

Which credentials can exploit this issue?

Exploitation requires remote authentication with a confined credential that has manage_roles: either a full-scope API key issued for named domains or a serveradmin account assigned a domain list. A credential belonging to one tenant can target custom roles used by accounts in other domains.

2

Can an attacker become a server administrator through this flaw?

No. Custom roles cannot contain the administer_server, administer_domain, or manage_roles permissions, so the confined credential cannot use custom-role changes to make itself or another account a server administrator.

3

What actions can the affected credential perform against custom roles?

It can modify a custom role held by accounts in other domains, create custom roles, and delete custom roles that are not assigned to any account. Modifying a cross-domain role can grant or remove permissions over another domain's mailboxes and settings.

4

What versions are affected and where is a fixed release indicated?

Progressive Robot hMailServer versions 6.3.4 through 6.3.6 are affected. The provided release reference identifies v6.3.7.

Contact

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Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
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