CVE-2026-114474
Received
Received - Intake
hMailServer External Account SPF/DMARC Bypass
Vulnerability report for CVE-2026-114474, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-21
Last updated on: 2026-10-21
Assigner: GitLab Inc.
Description
Description
Use of a less trusted source for the envelope sender in the external-account download of Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to have mail they write in the name of a domain the server hosts sent on by the server with an envelope sender at that domain, so that it passes the domain's SPF and DMARC at other receivers. A message the server downloads from an external POP3 or IMAP account has no SMTP envelope of its own, and the server took the address in its From header as its envelope sender, whatever that address was. A forward or redirect of the downloaded message to an outside address then left with that address as its envelope sender, which the Sender Rewriting Scheme leaves alone for a hosted domain, so that the receiver's SPF check passed for the forged domain, aligned even under strict alignment, with no non-default setting, host name record or DMARC policy needed. An attacker needs to know a mailbox elsewhere that an account here collects and forwards to an outside address; an account holder who adds an external account of their own can collect from a server of their own, which matters where SmtpAuthenticatedSenderCheck holds signed-in senders to their own addresses.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Progressive | Robot | Ltd hMailServer 6.0.0 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-348 | The product has two different sources of the same data or information, but it uses the source that has less support for verification, is less trusted, or is less resistant to attack. |
