GHSA-473Q-M89C-GHF8
Vulnerability from github – Published: 2026-10-28 19:49 – Updated: 2026-10-28 19:49Summary
With SslMode set to VerifyCA or VerifyFull with no configured CA certificate, an unvalidated TLS connection is treated as secure and a clear-text password can be sent before the certificate is checked. This can occur when relying on the password to validate a self-signed cert, e.g., MariaDB's zero-configuration TLS.
Impact
An attacker who can deploy a man-in-the-middle MySQL proxy presenting any self-signed certificate can capture the plaintext database password of a client that:
- uses
SslMode = VerifyCAorVerifyFull, and - does not use the
SslCaconnection string option, and - uses a non-empty password.
The attacker completes the TLS handshake with its own cert, requests a clear-text password authentication scheme (mysql_clear_password, or forces the caching_sha2_password/sha256_password clear-text fallback), and receives the password before the fingerprint check rejects the connection, defeating the man-in-the-middle protection VerifyFull is expected to provide.
Not affected: a configured CA (SslCa), CA-validated TLS, local connections (Unix socket / loopback), or empty passwords. Using SslMode set to Preferred or Required is out of scope (this is documented as not authenticating the server).
Workarounds
Provide SslCa with VerifyCA/VerifyFull, use a local/Unix-socket connection, or avoid clear-text authentication.
References
- https://mariadb.org/mission-impossible-zero-configuration-ssl/
{
"affected": [
{
"package": {
"ecosystem": "NuGet",
"name": "MySqlConnector"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.6.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-200"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-28T19:49:44Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "## Summary\n\nWith `SslMode` set to `VerifyCA` or `VerifyFull` with no configured CA certificate, an unvalidated TLS connection is treated as secure and a clear-text password can be sent before the certificate is checked. This can occur when relying on the password to validate a self-signed cert, e.g., MariaDB\u0027s [zero-configuration TLS](https://mariadb.com/docs/server/security/encryption/data-in-transit-encryption/zero-configuration-ssl).\n\n## Impact\n\nAn attacker who can deploy a man-in-the-middle MySQL proxy presenting any self-signed certificate can capture the plaintext database password of a client that:\n\n- uses `SslMode = VerifyCA` or `VerifyFull`, and\n- does not use the `SslCa` connection string option, and\n- uses a non-empty password.\n\nThe attacker completes the TLS handshake with its own cert, requests a clear-text password authentication scheme (`mysql_clear_password`, or forces the `caching_sha2_password`/`sha256_password` clear-text fallback), and receives the password before the fingerprint check rejects the connection, defeating the man-in-the-middle protection `VerifyFull` is expected to provide. \n\nNot affected: a configured CA (`SslCa`), CA-validated TLS, local connections (Unix socket / loopback), or empty passwords. Using `SslMode` set to `Preferred` or `Required` is out of scope (this is documented as not authenticating the server).\n\n## Workarounds\n\nProvide `SslCa` with `VerifyCA`/`VerifyFull`, use a local/Unix-socket connection, or avoid clear-text authentication.\n\n## References\n\n- https://mariadb.org/mission-impossible-zero-configuration-ssl/",
"id": "GHSA-473q-m89c-ghf8",
"modified": "2026-10-28T19:49:44Z",
"published": "2026-10-28T19:49:44Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/mysql-net/MySqlConnector/security/advisories/GHSA-473q-m89c-ghf8"
},
{
"type": "WEB",
"url": "https://github.com/mysql-net/MySqlConnector/commit/86503613fe3b72ae26c03dd1ea92f0e1e6e208f9"
},
{
"type": "PACKAGE",
"url": "https://github.com/mysql-net/MySqlConnector"
},
{
"type": "WEB",
"url": "https://github.com/mysql-net/MySqlConnector/releases/tag/2.6.1"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "MySqlConnector: Account password disclosed to a man-in-the-middle in zero-configuration TLS mode (clear-text password sent before certificate is verified)"
}
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