CVE-2026-55857
Description
A flaw was found in MariaDB Connector/J. A remote attacker or a man-in-the-middle server can exploit a vulnerability in the PAM dialog authentication mechanism. This flaw allows the attacker to coerce the connector into transmitting account passwords over an insecure connection when default configurations are used. Consequently, the user's password can be intercepted in cleartext, leading to sensitive information disclosure.
Statement
MariaDB Connector/J (org.mariadb.jdbc:mariadb-java-client) can be coerced by a hostile or man-in-the-middle server into performing PAM 'dialog' authentication over an unencrypted connection, transmitting the account password in cleartext. The affected path (SendPamAuthPacketFactory/SendPamAuthPacket) does not require secure transport and is reachable under the default configuration (sslMode=DISABLE, restrictedAuth unset). Verified TLS (sslMode=verify-ca or verify-full) and local Unix-socket connections are not exposed. Red Hat rates the impact of this flaw as Moderate because exploitation requires a man-in-the-middle network position and a plaintext connection.
Mitigation
Connect using sslMode=verify-full (or verify-ca) with a properly configured server certificate and trust store, or use a local Unix socket, so the connector never negotiates PAM dialog authentication over cleartext. Setting restrictedAuth to exclude the dialog/mysql_clear_password plugins also prevents disclosure. A fixed MariaDB Connector/J (2.7.14, 3.3.5, 3.4.3, or 3.5.9, as appropriate for the branch in use) additionally addresses the issue.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | 5.9 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Understanding the Weakness (CWE)
Integrity,Confidentiality
Technical Impact: Read Application Data; Modify Files or Directories
Anyone can read the information by gaining access to the channel being used for communication. Many communication channels can be "sniffed" (monitored) by adversaries during data transmission. For example, in networking, packets can traverse many intermediary nodes from the source to the destination, whether across the internet, an internal network, the cloud, etc. Some actors might have privileged access to a network interface or any link along the channel, such as a router, but they might not be authorized to collect the underlying data. As a result, network traffic could be sniffed by adversaries, spilling security-critical data.
Integrity,Confidentiality
Technical Impact: Read Application Data; Modify Files or Directories; Other
When full communications are recorded or logged, such as with a packet dump, an adversary could attempt to obtain the dump long after the transmission has occurred and try to "sniff" the cleartext from the recorded communications in the dump itself. Even if the information is encoded in a way that is not human-readable, certain techniques could determine which encoding is being used, then decode the information.
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