CVE-2026-126610: Progressive Robot hMailServer · Improper Certificate Validation
Affects Progressive Robot hMailServerSource CVE Database V5
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.4 High.
Data as of 11 Nov 2026, 08:49 UTC
Thin evidence
One scorer or none| CNA (GitLab) | CVSS 3.1 | 7.4 |
|---|
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 11 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Progressive Robot LtdhMailServer | Affected
| Fixed in– |
AI-suggested
A fix is available by upgrading MariaDB Connector/C to version 3.4.11 or later, which addresses the certificate validation issues (MariaDB's CONC-853). Users should also ensure that the CA file name does not contain characters outside ASCII on Linux or above U+00FF on Windows to avoid the filename conversion issue. If upgrading is not immediately possible, consider reverting to default TlsMode settings (prefer) which do not enforce certificate validation and thus are not affected by this vulnerability. Monitor vendor advisories for official patches or updates to hMailServer that address this issue directly.
Description
CVE-2026-126610 is a vulnerability in Progressive Robot Ltd's hMailServer versions 6.3.4 through 6.3.7 when configured with a MySQL or MariaDB database and TlsMode=verify-full. The issue arises because the server fails to provide the database client with the correct CA file if the CA file name contains non-ASCII characters on Linux or characters above U+00FF on Windows. This causes the client to verify the database server's certificate against the system trust store rather than the intended CA, allowing an attacker who can intercept the database connection to read and modify traffic by presenting a certificate from any authority or even a self-signed certificate under certain conditions. The vulnerability is related to improper certificate validation (CWE-295) and is exacerbated by specific behaviors in MariaDB Connector/C versions 3.4.2 to 3.4.10.