CVE-2026-114475: Missing Authorization in hMailServer
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
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Progressive Robot hMailServerto a version that resolves this vulnerability.Fixed in 6.3.7 - Configuration
Keep the REST API disabled by setting RestApiPort=0 where it is not needed.
hMailServer REST API RestApiPort = 0 - 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.
- 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
Frequently Asked Questions
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.
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.
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.
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.