# CVE-2026-55856: MariaDB Connector/J: Cleartext password disclosure to a MITM on the initial-handshake > An active man-in-the-middle can steal database passwords during the initial handshake if specific SSL verification settings are used without explicit trust store configuration. - **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 28 Aug 2026 - **Updated:** 31 Aug 2026 - **Also known as:** CLEANSTART-2026-EO42175, CLEANSTART-2026-MO09576, CLEANSTART-2026-WK92000, CLEANSTART-2026-YJ93143, ECHO-b9d6-8b57-95e5, GHSA-g9jj-cgmh-9f38, MINI-3g6h-r8qp-ff7r, MINI-4m78-3w26-qx5g, MINI-5h3x-prm3-pm9p, MINI-5hqm-j3rx-fq2v, MINI-732r-8pp4-p79w, MINI-8jmm-qmv4-q2mh, MINI-f4cc-9pp7-qj9h, MINI-f9ff-4xfx-44r4, MINI-frpg-f8vm-4vrj, MINI-jc9r-h63f-h825, MINI-m4x6-4pcf-55h4, MINI-pfwf-932w-rjwj, MINI-r2mp-v37c-hhcv, MINI-rqw9-22wh-f5v7, MINI-vvxf-ggrw-qfxf ## What is CVE-2026-55856? CVE-2026-55856 is a medium-severity vulnerability in mariadb-corporation mariadb-connector-j, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. Prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9, when a Java application connects with sslMode=verify-full or sslMode=verify-ca, supplies a password, and does not configure serverSslCert or trustStore, Connector/J can accept an untrusted self-signed certificate through the fallbackToSystemTrustStore=true ephemeral trust manager and record its certFingerprint for later identity binding. The OK-packet and authentication-switch paths enforce the certificate fingerprint, but the initial-handshake path does not. HandshakeResponse.encode() can therefore build and send a mysql_clear_password response before checking certFingerprint != null && !isMitMProof(), sslMode, or whether the authentication plugin is resistant to a man-in-the-middle, and the initial path also bypasses restrictedAuth. An active man-in-the-middle or hostile server can present a self-signed certificate, claim to be MariaDB, select mysql_clear_password as the initial authentication plugin, and receive the full database password before the connection is rejected. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9. Weakness: CWE-522 (Insufficiently Protected Credentials) ## Which versions are affected by CVE-2026-55856? 8 open source packages ship an affected version, including org.mariadb.jdbc:mariadb-java-client. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `org.mariadb.jdbc:mariadb-java-client` | Maven | All versions | 2.7.14 | | `org.mariadb.jdbc:mariadb-java-client` | Maven | All versions | 2.7.14 | | `org.mariadb.jdbc:mariadb-java-client` | Maven | From 3.0.0 | 3.3.5 | | `org.mariadb.jdbc:mariadb-java-client` | Maven | From 3.0.0 | 3.3.5 | | `org.mariadb.jdbc:mariadb-java-client` | Maven | From 3.4.0 | 3.4.3 | | `org.mariadb.jdbc:mariadb-java-client` | Maven | From 3.4.0 | 3.4.3 | | `org.mariadb.jdbc:mariadb-java-client` | Maven | From 3.5.0 | 3.5.9 | | `org.mariadb.jdbc:mariadb-java-client` | Maven | From 3.5.0 | 3.5.9 | ## How do I fix CVE-2026-55856? Upgrade org.mariadb.jdbc:mariadb-java-client to a fixed version for your release line: 2.7.14, 3.3.5, 3.4.3 or 3.5.9. ## Is CVE-2026-55856 being exploited? There is no known exploitation of CVE-2026-55856 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-55856 and fix it if it is affected. What it is: CVE-2026-55856 is a medium-severity vulnerability in mariadb-corporation mariadb-connector-j, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-55856 in the wild and no public exploit code. Affected packages and fixed versions: - org.mariadb.jdbc:mariadb-java-client (Maven): affected all versions; fixed in 2.7.14 - org.mariadb.jdbc:mariadb-java-client (Maven): affected all versions; fixed in 2.7.14 - org.mariadb.jdbc:mariadb-java-client (Maven): affected from 3.0.0; fixed in 3.3.5 - org.mariadb.jdbc:mariadb-java-client (Maven): affected from 3.0.0; fixed in 3.3.5 - org.mariadb.jdbc:mariadb-java-client (Maven): affected from 3.4.0; fixed in 3.4.3 - org.mariadb.jdbc:mariadb-java-client (Maven): affected from 3.4.0; fixed in 3.4.3 - org.mariadb.jdbc:mariadb-java-client (Maven): affected from 3.5.0; fixed in 3.5.9 - org.mariadb.jdbc:mariadb-java-client (Maven): affected from 3.5.0; fixed in 3.5.9 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-55856/ (Markdown: https://insights.sbomify.com/CVE-2026-55856/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55856 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55856 - OSV: https://osv.dev/vulnerability/CVE-2026-55856 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-55856/ Summaries are generated and may contain mistakes; the official description above is the record.