CVE-2026-104704Cleartext Transmission of Sensitive Information in hMailServer
Updated under an hour ago ()
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It affects Progressive Robot Ltd hMailServer. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.15%, higher than 4% of scored CVEs.
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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
- 7.4 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- Weakness (CWE)
- CWE-319
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.15% (percentile 4)
- Assigned by
- GitLab
- NVD analysis
- Deferred
- Record last updated
- Oct 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Progressive Robot Ltd hMailServer progressive_robot:hmailserver (from the name) | from 6.0.0 before 6.3.6 | CNA record |
References
- https://gitlab.com/hmailserver/hmailserver/-/work_items/61
- https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.