CVE-2026-55856: Credential Exposure (CVSS 5.9)

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.

Is your site exposed to CVE-2026-55856?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.13%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-522 CWE-522

References

Other References

https://github.com/mariadb-corporation/mariadb-connector-j/commit/149ec6a626376214966c01f42d48be1b80d06056 https://github.com/mariadb-corporation/mariadb-connector-j/commit/d90b9872322c76b05a48219be66bff1d33102f8a https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3 https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9 https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-g9jj-cgmh-9f38 https://hackerone.com/reports/3777370 https://jira.mariadb.org/browse/CONJ-1325

Frequently Asked Questions

What is CVE-2026-55856? +

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. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-55856? +

CVE-2026-55856 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0022, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-55856? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-15621

Insufficiently Protected Credentials in Sparx Systems Pty Ltd. Sparx Enterprise Architect. Client does not verify the receiver of OAuth2 credentials …

CVE-2025-15622

Insufficiently Protected Credentials vulnerability in Sparx Systems Pty Ltd. Sparx Enterprise Architect. Client reveals plaintext OAuth2 client secretDesktop client decodes …

CVE-2026-4387

StrongDM Desktop Application before 23.74.0 (Desktop Client before 53.77.0) on Microsoft Windows stores authentication state, including a JSON Web Token …

CVE-2026-46458

ICU Scandinavia Boomerang is vulnerable to an information disclosure flaw where sensitive credential files are exposed via static HTTP. This …

CVE-2026-8368

LWP::UserAgent versions before 6.83 for Perl leak Authorization and Proxy-Authorization headers on cross-origin redirects. On a 3xx response, the redirect …

CVE-2024-12799

Insufficiently Protected Credentials vulnerability in OpenText Identity Manager Advanced Edition on Windows, Linux, 64 bit allows Privilege Abuse. This vulnerability …

CVE-2026-55856