---
id: "CVE-2026-126611"
page: "https://infrastack.ai/live/CVE-2026-126611"
kind: "vulnerability"
aliases: ["CVE-2026-126611"]
title: "hMailServer: local impostor can capture database password under verify-full"
severity: "high"
cvss: 7.0
epss: null
exploited: false
status: "open"
category: "runtime"
products: [{"name": "hMailServer", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["hmailserver", "mariadb", "mysql", "runtime", "self-hosted", "windows"]
not_affected_if: ["default-config", "no-mysql-or-mariadb", "remote-database-only", "tls-prefer"]
published_at: "2026-11-11T09:17:12+00:00"
first_seen_at: "2026-11-11T09:26:48+00:00"
updated_at: "2026-11-11T09:28:41+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126611", "first_seen_at": "2026-11-11T09:26:48+00:00"}]
exploit_sources: []
---

# hMailServer: local impostor can capture database password under verify-full

Link for people: https://infrastack.ai/live/CVE-2026-126611 (this .md is for agents)

hMailServer 6.3.4 through 6.3.7 with MySQL or MariaDB and TlsMode=verify-full but no TlsCaFile fails to verify the database server's certificate on local connections. A local attacker who impersonates the database can capture the sign-in password and read or modify traffic between hMailServer and its database.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:hMailServer affected range not listed fixed no fixed version listed

## How to check

- Check the hMailServer version: it is affected from `6.3.4` through `6.3.7`.
- Check whether TlsMode is set to `verify-full` and no TlsCaFile is configured.
- Check whether the Server setting points to 127.0.0.1, ::1, localhost, a Unix socket, a named pipe (`.`), or a list containing such an entry.
- On Windows builds, the bundled MariaDB Connector/C is `3.4.9` (6.3.4 to 6.3.6) or `3.4.11` (6.3.7).

## Timeline

- 2026-11-11T09:26:48+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-126611

## From the sources

Progressive Robot hMailServer 6.3.4 through 6.3.7, with a MySQL or MariaDB database, TlsMode=verify-full and no TlsCaFile, does not verify the database server's certificate's issuer or name when the connection is one that MariaDB Connector/C treats as local - Server= set to 127.0.0.1, ::1 or localhost (on Linux a Unix socket), to . on Windows (a named pipe), or to a comma-separated list of servers that holds such an element - which allows a local attacker who can stand in for the database server, for example by listening on its port while it is stopped or restarting, to receive the database sign-in, the password included, and to read and modify the traffic between hMailServer and its database. hMailServer applied verify-full by turning the client's certificate verification on without a CA file, but MariaDB Connector/C 3.4.1 and later, on a connection they treat as local and with no CA file, accept any certificate within its validity period that is self-signed or sent with its own root, for any name (Connector/C 3.4.2 to 3.4.10 also one whose issuer they cannot find), so the client accepted the certificate an impostor made, asked no proof of the password and allowed a switch to an authentication method that sends the password unhashed, while hmailserver --check-database said the certificate had been checked against the system's trust store and the application log that it had been checked. The Windows builds bundle Connector/C 3.4.9 (6.3.4 to 6.3.6) and 3.4.11 (6.3.7); on Linux the distribution's client is used, and Connector/C 3.3 and 3.4.0 and Oracle's MySQL client are not affected. The configuration is not the default: TlsMode defaults to prefer, which checks no certificate.

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