Summary
org.mariadb:r2dbc-mariadb vulnerable to cleartext password disclosure to a man-in-the-middle server (clear-text auth plugins not gated on a secure transport)
The connector does not gate clear-text password authentication plugins on transport encryption. A hostile or man-in-the-middle MariaDB server can request a clear-text plugin over an unencrypted (plain-TCP) connection, and the driver responds with the user's password in cleartext on the wire.
Details
The driver does not require a secure transport before using clear-text-password authentication plugins. A hostile or man-in-the-middle server can issue an AuthSwitchRequest naming mysql_clear_password or dialog (PAM) over a plain-TCP, unencrypted connection, and the driver replies with the user's password as cleartext bytes on the wire.
The root cause is that the AuthenticationPlugin interface declares no capability for a plugin to require a secure connection. Because no such gate exists, clear-text plugins run regardless of whether the connection is encrypted.
Workarounds
Until you can upgrade, configure certificate verification explicitly: provide the server/CA certificate and use a verifying SSL mode (e.g. VERIFY_CA / VERIFY_FULL) so the connection is encrypted and the server's identity is established before credentials are sent.
Credit
Reported by Yalguun Tumenkhuu (@fg0x0).
Impact
The account password is transmitted in cleartext to the peer. An on-path attacker (MITM) who presents themselves as the server can capture the password during the authentication handshake. The disclosed credentials can subsequently be used to authenticate directly against the database server.
CVE-2026-55860 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.4.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Fixed in 1.4.1. Clear-text authentication plugins (mysql_clear_password, dialog/PAM) now require a secure connection: the AuthenticationPlugin contract can declare that a plugin requires a secure transport, and such plugins are permitted only over an encrypted connection. Upgrade to 1.4.1 or later.
Frequently Asked Questions
- What is CVE-2026-55860? CVE-2026-55860 is a medium-severity security vulnerability in org.mariadb:r2dbc-mariadb (maven), affecting versions < 1.4.1. It is fixed in 1.4.1.
- How severe is CVE-2026-55860? CVE-2026-55860 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of org.mariadb:r2dbc-mariadb are affected by CVE-2026-55860? org.mariadb:r2dbc-mariadb (maven) versions < 1.4.1 is affected.
- Is there a fix for CVE-2026-55860? Yes. CVE-2026-55860 is fixed in 1.4.1. Upgrade to this version or later.
- Is CVE-2026-55860 exploitable, and should I be worried? Whether CVE-2026-55860 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-55860 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-55860? Upgrade
org.mariadb:r2dbc-mariadbto 1.4.1 or later.