CVE.org (no NVD analysis yet)· CNA GitLab

CVE-2026-104660: Missing Authorization in hMailServer

HighCVSS 7.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.10% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Progressive Robot Ltd hMailServer 6.3.6.

Low priority for now. Upgrade to Progressive Robot Ltd hMailServer 6.3.6 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Missing authorization on COM objects in Progressive Robot hMailServer 6.0.0 through 6.3.5 (Windows only) lets a local interactive user with no hMailServer credential read and write arbitrary files as the service account and queue mail as any sender. The service registers its COM classes with no DCOM access or launch permission and calls CoInitializeSecurity with no security descriptor, so any user logged on at the console or over Remote Desktop can activate the classes in the running service; a hMailServer.Message, its Attachments and Attachment, and a hMailServer.FetchAccount created this way carry a credential that never authenticated. Attachments.Add(path) and Attachment.SaveAs(path) performed no authorization check, and Message.Save/Copy and FetchAccount.AccountID/Save performed none either up to 6.3.3 and from 6.3.4 treated a holder with no credential as the server's own event-script host. Because the service does not impersonate the COM caller, Attachments.Add reads any file the service account can read and returns it, Attachment.SaveAs writes attacker-chosen bytes to any path it can write (on a LocalSystem installation, code execution as SYSTEM), Message.Save queues outbound mail from any address past the SMTP checks, and FetchAccount attaches a mail-fetch job to any mailbox. The objects an Application handed out behave the same once a later Authenticate on that Application fails.

Broken access control (IDOR)

EUVD-2026-94833

Published: Oct 8, 2026
Updated: Oct 8, 2026
EPSS: 0.1% · 1th percentile
CWE: CWE-862

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitLab: 7.8; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitLab). Independent of NVD's CPE analysis and usually ahead of it.

Progressive Robot Ltd hMailServer
- 6.0.0 and later · before 6.3.6affected · semver

Same product

progressive robot ltd: all records

Other highest-scoring records for the same primary product.

CVE-2026-100741Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection') in hMailServer
40Plan
CVE-2026-126617Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') in hMailServer
35Monitor
CVE-2026-114489Missing Authorization in hMailServer
32Monitor

Published before and after this one in the same product

← EarlierCVE-2026-104658Oct 8, 2026 · Reliance on Untrusted Inputs in a Security Decision in hMailServer
31Monitor
← EarlierCVE-2026-104659Oct 8, 2026 · Origin Validation Error in hMailServer
30Monitor
Later →CVE-2026-104704Oct 8, 2026 · Cleartext Transmission of Sensitive Information in hMailServer
29Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Progressive Robot Ltd hMailServer	6.3.6	Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.