CVE-2026-104704: high-severity vulnerability in Progressive Robot Ltd hMailServer
Cleartext Transmission of Sensitive Information in hMailServer
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.4epss 0.1%
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Affected products
Progressive Robot Ltd · hMailServerRelated CVEs — Progressive Robot Ltd hMailServer
In the same product, most dangerous first.
CVE-2026-100741CRITICALImproper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection') in hMailServerEPSS 1.7%CVE-2026-107585MEDIUMAllocation of Resources Without Limits or Throttling in hMailServerEPSS 0.4%CVE-2026-107576HIGHInefficient Algorithmic Complexity in hMailServerEPSS 0.4%CVE-2026-107577HIGHLoop with Unreachable Exit Condition ('Infinite Loop') in hMailServerEPSS 0.4%CVE-2026-107574HIGHInefficient Algorithmic Complexity in hMailServerEPSS 0.4%CVE-2026-107575MEDIUMInefficient Algorithmic Complexity in hMailServerEPSS 0.4%