CVE-2026-55854 is a medium-severity (CVSS 5.9) CWE-319 vulnerability in mariadb. O3 Security confirms whether CVE-2026-55854 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
MariaDB has Cleartext Transmission of Sensitive Information and Insufficiently Protected Credentials
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
mariadbnpmDescription
Summary
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.
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).
Patches
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.
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).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | mariadb | all versions | 3.2.4 |
| 📦npm | mariadb | ≥ 3.3.0&&< 3.3.3 | 3.3.3 |
| 📦npm | mariadb | ≥ 3.4.0&&< 3.4.6 | 3.4.6 |
| 📦npm | mariadb | ≥ 3.5.0&&< 3.5.3 | 3.5.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mariadb. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update mariadb to 3.2.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55854 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-55854 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-55854. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-55854 in your dependencies?
O3 detects CVE-2026-55854 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.