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01 Record

CVE-2026-107584

Not Failing Securely ('Failing Open') in hMailServer

HighPUBLISHEDCNA: GitLab
CNA base score7.4 CVSS v3.xCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

02 Description

Not Failing Securely ('Failing Open') in hMailServer

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.15% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 3.7% of scored records. A rank, not a probability.
NVD base score
7.4 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD analysis status
Deferred. NVD last modified this record on 2026-10-08.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-10-08 11:49Z21 DAYS AGO
Last updated
2026-10-08 17:34Z20 DAYS AGO
Reserved
2026-10-08
Assigning CNA
GitLab
Record state
PUBLISHED
Severity
High (CVSS 7.4)
CNA CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weaknesses
  • CWE-636Not Failing Securely ('Failing Open')Class
Data version
5.2
Document digest
2552b05317f42b860130cb91ee90634e9dacec8141ce392d7a72fa3b61c24688

05 Affected products

VendorProductVersionsPlatforms
Progressive Robot LtdhMailServer6.0.0 to < 6.3.6—

06 References

07 Remediation

Upgrade to hMailServer 6.3.6, which treats an incomplete, unsigned or unproven DNSSEC answer for a TLSA or MX lookup under a signed zone as indeterminate, does not use a mail exchanger whose lookup was indeterminate, defers the delivery when none is left, delivers only to mail exchangers named by a DNSSEC-validated MX record set, and (for a host whose DNS servers are IPv6 only) asks those IPv6 servers. Until then, for each recipient domain whose mail must be protected, an SMTP route that names its mail exchangers with the connection security 'STARTTLS (required)', with remote certificate verification on (VerifyRemoteSslCertificate=1), prevents delivery in cleartext or to another host for that domain; and the server's DNS resolver should be one reached over a trusted path, such as a validating resolver on the same host.