Vulnerabilidad · Publicado 08/10/2026
hMailServer versiones 6.0.0 a 6.3.5 no implementa correctamente la validación DANE/TLSA para entregas SMTP salientes, permitiendo degradación a conexiones sin TLS cuando los registros DNSSEC no contienen registros DANE-EE. Esto expone las comunicaciones de correo en tránsito a empresas mexicanas y latinoamericanas que usan este servidor de correo, comprometiendo la confidencialidad de mensajes según RFC 7672.
Progressive Robot hMailServer 6.0.0 through 6.3.5 does not enforce TLS for outbound SMTP delivery to a mail exchanger whose DNSSEC-validated TLSA records contain no DANE-EE (usage 3) record, contrary to RFC 7672 section 2.2. The server used only DANE-EE records and treated a validated TLSA record set consisting of DANE-TA (usage 2) or otherwise unusable records as if no records were published, so delivery to such a host fell back to opportunistic TLS. An attacker with an active position on the network path between the server and the recipient's mail exchanger can suppress or break the STARTTLS negotiation and cause messages to be delivered in cleartext, where they can be read and modified.
Score: 7.4/10 — Severidad: HIGH — Estado NIST: Received
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE-319
Publicado en NIST NVD.