CVE-2026-104660Missing Authorization in hMailServer
Updated under an hour ago ()
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It affects Progressive Robot Ltd hMailServer. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.11%, higher than 1% of scored CVEs.
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-862
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.11% (percentile 1)
- Assigned by
- GitLab
- NVD analysis
- Deferred
- Record last updated
- Oct 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Progressive Robot Ltd hMailServer progressive_robot:hmailserver (from the name) | from 6.0.0 before 6.3.6 | CNA record |
References
- https://gitlab.com/hmailserver/hmailserver/-/work_items/59
- https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.