{"id":"CVE-2026-114478","summary":"Unintended Proxy or Intermediary ('Confused Deputy') in hMailServer","details":"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.","modified":"2026-10-22T02:48:51.775045867Z","published":"2026-10-21T15:12:35.847Z","database_specific":{"cna_assigner":"GitLab","cwe_ids":["CWE-441"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/114xxx/CVE-2026-114478.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/114xxx/CVE-2026-114478.json"},{"type":"PACKAGE","url":"https://gitlab.com/hmailserver/hmailserver"},{"type":"WEB","url":"https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.7"},{"type":"WEB","url":"https://gitlab.com/hmailserver/hmailserver/-/work_items/90"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-114478"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://gitlab.com/hmailserver/hmailserver","events":[{"introduced":"e4b7163189ac6ce365bb954cf3e264e2e3105a18"},{"last_affected":"e3c448aa66fc310b74d076884d54fae951296915"}],"database_specific":{"extracted_events":[{"strategy":"StandardRange","range":[{"introduced":"6.0.0"},{"last_affected":"6.3.6"}],"source":"AFFECTED_FIELD"}]}}],"versions":["v6.3.6","v6.3.5","v6.3.4","v6.3.3","v6.3.2","build-inputs-1","v6.3.1","v6.3.0","v6.2.28","v6.2.27","v6.2.26","v6.2.25","v6.2.24","v6.2.23-alpha2","v6.2.23-alpha1","v6.2.22-pre6","v6.2.22-pre5","v6.2.22-pre4","v6.2.22-pre3","v6.2.22-pre2","v6.2.22-pre1","v6.2.21","v6.2.20","v6.2.19","v6.2.18","v6.2.17","v6.2.16","v6.2.15","v6.2.14","v6.2.13","v6.2.12","v6.2.11","v6.2.10","v6.2.9","v6.2.8","v6.2.7","v6.2.6","v6.2.5","v6.2.4","v6.2.3","v6.2.2","v6.2.1","v6.2.0","v6.1.0","v6.0.0-B4","v6.0.0-B3","v6.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-114478.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}