Answer in brief
CVE-2026-126609 records a High severity (CVSS 7.5) vulnerability in Improper Certificate Validation in hMailServer. The current sources do not mark it as known exploited. The current feed maps Progressive Robot Ltd/hMailServer (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Progressive Robot Ltd/hMailServer (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Progressive Robot Ltd/hMailServergeneric | >=6.2.25 <=6.3.7 | Not reported |
Published upstream
Nov 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 11, 2026
Progressive Robot hMailServer 6.2.25 through 6.3.7 on Windows, with a PostgreSQL database, the connection's sslmode require, verify-ca or verify-full, and a root certificate file named by PostgreSQLSslRootCert (from 6.2.25) or, with TlsMode=verify-full and neither PostgreSQL key set, by TlsCaFile (from 6.3.4), hands the file's name to libpq as bytes in the system's ANSI code page (up to 6.3.5 as Latin-1 bytes, which on code page 1252 are the code page's own for U+00A0 to U+00FF), and libpq looks for the file by those bytes and then hands the same bytes to OpenSSL, whose file opening on Windows reads a name as UTF-8 first and opens the file at that reading when one is there. When every byte of the name outside ASCII also reads as UTF-8 - for example U+00C3 U+00A9, the bytes C3 A9 on code page 1252, which are U+00E9 in UTF-8 - the database server's certificate was checked against the file at that other name whenever one was there, which allows a local attacker who can create that file but cannot change the configured one, as any user can by default beside a file an administrator keeps under ProgramData, or beside a folder directly under the system drive's root whose permissions the administrator restricted, and who can intercept the connection to the database server or stand in for it, to have hMailServer trust a certificate authority of the attacker's own and read and modify the traffic between hMailServer and its database, the database password included; the file alone, holding no authority that issued the database server's certificate, stops hMailServer from connecting to its database. The same applies in 6.3.4 through 6.3.7 to TlsCaFile when an Oracle MySQL client library has been put in place of the bundled MariaDB Connector/C, since that client opens the file through OpenSSL in the same way; the bundled MariaDB Connector/C opens the file in the code page and is not affected, and neither are the Linux builds. The configuration is not the default: by default no root certificate file is named.
Quoted source text, attributed separately from HOL analysis.