Summary
MariaDB has Cleartext Transmission of Sensitive Information and Insufficiently Protected Credentials
When PAM (dialog) authentication is used, the connector can be coerced into sending the account password in cleartext over an insecure connection. A hostile or man-in-the-middle server can trigger this with the default configuration, disclosing the user's password.
Details
The mysql_clear_password plugin is gated behind a secure connection: the driver refuses to transmit the password in cleartext over plain TCP. The sibling PAM plugin handler (SendPamAuthPacketFactory, server-side plugin name dialog) did not override that gate and inherited the default value false, so it was not subject to the same secure-transport requirement.
As a result, a hostile or man-in-the-middle server can issue an Authentication Switch Request for the dialog plugin over plain TCP, and the driver responds with the user's password in cleartext. With the default configuration (sslMode=DISABLE, restrictedAuth=null) this is reachable with no non-default options.
Am I affected?
You are affected if all of the following hold:
You use mariadb Connector/Node.js at a version below the patched release(s).
Connections can occur over an insecure transport: plain TCP (sslMode=DISABLE), or a TLS mode that establishes server identity only via self-signed-certificate fingerprint validation.
An attacker can occupy an on-path (MITM) position, or otherwise cause the client to connect to a server they control, and present an Authentication Switch Request for the dialog plugin.
Connections over properly verified TLS or a local Unix socket are not exposed to this vector.
Workarounds
If you cannot upgrade immediately:
- Restrict the permitted authentication plugins via restrictedAuth so dialog cannot be negotiated over an insecure transport.
Avoid PAM (dialog) authentication over plain TCP.
###Credit
Reported by Yalguun Tumenkhuu (@fg0x0).
Impact
Disclosure of the authenticating account's password in cleartext to an on-path or hostile server. The captured credentials can then be reused to authenticate to the database (and, if reused elsewhere, beyond it).
CVE-2026-55854 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 (3.2.4, 3.3.3, 3.4.6, 3.5.3); 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.
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Fixed in 3.2.4, 3.3.3, 3.4.6, and 3.5.3. Upgrade to the patched release on your branch (3.5.x → 3.5.3, 3.4.x → 3.4.6, 3.3.x → 3.3.3, 3.2.x and earlier → 3.2.4). PAM (dialog) is now treated exactly like mysql_clear_password: it may only run over a secure transport. SendPamAuthPacketFactory overrides the secure-required flag to true, and the authentication dispatcher permits a secure-required plugin only when the connection is TLS or a local Unix socket. The pre-existing check that blocks non-MITM-proof plugins when server identity relies solely on self-signed-certificate fingerprint validation continues to apply. Net effect: PAM is allowed over TLS or a Unix socket, and rejected over plain TCP or fingerprint-only connections.
Frequently Asked Questions
- What is CVE-2026-55854? CVE-2026-55854 is a medium-severity security vulnerability in mariadb (npm), affecting versions < 3.2.4. It is fixed in 3.2.4, 3.3.3, 3.4.6, 3.5.3.
- How severe is CVE-2026-55854? CVE-2026-55854 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 mariadb are affected by CVE-2026-55854? mariadb (npm) versions < 3.2.4 is affected.
- Is there a fix for CVE-2026-55854? Yes. CVE-2026-55854 is fixed in 3.2.4, 3.3.3, 3.4.6, 3.5.3. Upgrade to this version or later.
- Is CVE-2026-55854 exploitable, and should I be worried? Whether CVE-2026-55854 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-2026-55854 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-2026-55854?
- Upgrade
mariadbto 3.2.4 or later - Upgrade
mariadbto 3.3.3 or later - Upgrade
mariadbto 3.4.6 or later - Upgrade
mariadbto 3.5.3 or later
- Upgrade