{"id":"CVE-2026-114478","revision":"2c73bc494e77469c883d96e96ae3739b","records":[{"revision":"2c73bc494e77469c883d96e96ae3739b","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-114478","aliases":[],"title":"Unintended Proxy or Intermediary ('Confused Deputy') in hMailServer","description":"Insufficient preservation of the original sender in the forwarding of Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to have mail they write, naming in its From an address at a domain the server hosts, delivered to other receivers as passing that domain's DMARC policy. When the server sent on a copy of mail that came from outside - an account's forward, a mail rule's forward, a Sieve redirect, a list's copy, or an alias or list expanding to an outside address - it could give the copy an SMTP identity in the organisation of the domain the copy's From names, whatever the message's origin: with the Sender Rewriting Scheme or the rewrite of the envelope sender on forwarding enabled (both off by default), an address at the forwarding domain; for a list, its bounce address; for a message with an empty envelope sender, none, under the server's own host name; and an envelope sender the message came with at a subdomain of a hosted domain was kept. Where that identity's SPF record authorises the server, other receivers' SPF check of the copy passed for a domain aligned with the From, and DMARC passed with it, although the message had not passed DMARC when the server received it. Exploitation needs a forward, redirect, alias or list that carries the hosted domain's mail to an outside address, and one of: SRS or the envelope rewrite enabled; a list whose bounce address is in the domain's organisation; an envelope sender at a subdomain whose SPF record authorises the server; or, for an empty envelope sender, an SPF record that authorises the server under its host name. The DKIM route to the same result is CVE-2026-107567.","state":0,"publishedAt":"2026-10-21T15:12:35.847+00:00","modifiedAt":"2026-10-21T15:12:35.847+00:00","affected":[{"ecosystem":"Vendor product","name":"hMailServer","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Progressive Robot Ltd\",\n                    \"product\": \"hMailServer\",\n                    \"repo\": \"https://gitlab.com/hmailserver/hmailserver\",\n                    \"versions\": [\n                        {\n                            \"version\": \"6.0.0\",\n                            \"status\": \"affected\",\n                            \"lessThanOrEqual\": \"6.3.6\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","score":5.9,"severity":"MEDIUM"}],"references":["https://gitlab.com/hmailserver/hmailserver/-/work_items/90","https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.7"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-114478","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-114478","identifiers":["CVE-2026-114478"]},"retained":false,"historicalAffected":[]}],"coverage":[]}