Authorization Flaw in Progressive Robot hMailServer by hMailServer
CVE-2026-114477

4.3MEDIUM

Key Information:

Vendor

Progressive Robot Ltd

Status
Hmailserver
Vendor
CVE Published:
21 October 2026

What is CVE-2026-114477?

A security gap in the Progressive Robot version of hMailServer permits remote authenticated users whose credentials are limited to specific domains to access the server's overall traffic history. The vulnerability is present in the REST metrics route, where GET requests to /api/v1/metrics/history can reveal aggregate traffic counters from the last 30 days. Since these counters are server-wide and do not include domain-specific data, unauthorized users—including domain administrators or auditor roles—can view sensitive operational metrics intended solely for their domains. This flaw underscores the importance of proper authorization checks in API endpoints to protect server integrity.

Affected Version(s)

hMailServer 6.2.25 <= 6.3.6

References

https://gitlab.com/hmailserver/hmailserver/-/work_items/96
https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.7

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Found in the hMailServer project's own security review (Progressive Robot Ltd)
.