MySqlConnector: Account password disclosed to a man-in-the-middle in zero-configuration TLS mode (clear-text password sent before certificate is verified)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · 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 · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary 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 = VerifyCA` or `VerifyFull`, and - does not use the `SslCa` connection 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…

Published by the source

28 Oct 2026, 19:49 UTC

Last modified by the source

28 Oct 2026, 20:00 UTC

Source last checked

29 Oct 2026, 06:55 UTC

1. Revision 2 · amended · 29 Oct 2026

   Amended from osv record GHSA-473q-m89c-ghf8

2. Revision 1 · created · 28 Oct 2026

   Published from ghsa record GHSA-473q-m89c-ghf8

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-473q-m89c-ghf8

Advisory: MySqlConnector: Account password disclosed to a man-in-the-middle in zero-configuration TLS mode (clear-text password sent before certificate is verified)
IDs: GHSA-473q-m89c-ghf8
Record: https://patchnext.com/advisories/ghsa-473q-m89c-ghf8 (revision 2, source checked 29 Oct 2026, 06:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mysqlconnector 2.6.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet mysqlconnector: affected < 2.6.1; fixed in 2.6.1

## Suggested inspection (read-only)
- NuGet mysqlconnector: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mysqlconnector.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-473q-m89c-ghf8 (GitHub-reviewed advisory GHSA-473q-m89c-ghf8 lists affected ranges: NuGet mysqlconnector >=0 <2.6.1)
- Verified: https://osv.dev/vulnerability/GHSA-473q-m89c-ghf8 (OSV record GHSA-473q-m89c-ghf8 lists affected ranges: NuGet mysqlconnector >=0 <2.6.1 (fixed))

Commands are suggestions: review each one before running it.