Command Injection in MariaDB Server via wsrep_notify_cmd

Executive Summary

CVE-2026-49261 is a critical vulnerability in MariaDB server related to the `wsrep_notify_cmd` feature. When this feature is enabled, the server executes shell commands embedded in the name of a joiner node without proper sanitization. This allows an attacker to inject arbitrary operating system commands remotely by including shell metacharacters in peer-supplied fields such as wsrep_node_name and wsrep_node_incoming_address.

The vulnerability affects multiple MariaDB versions including 10.6.1 through 10.6.26, 10.11.1 through 10.11.17, 11.4.1 through 11.4.11, 11.8.1 through 11.8.7, and 12.3.1. It has been fixed in later versions by validating and rejecting unsafe values before executing commands.

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Compliance Impact

The vulnerability allows remote attackers to execute arbitrary shell commands on affected MariaDB servers without privileges or user interaction, leading to a complete compromise of confidentiality, integrity, and availability.

Such a critical security flaw could result in unauthorized access to sensitive data, disruption of services, and potential data breaches, which may violate compliance requirements under standards like GDPR and HIPAA that mandate protection of personal and health information.

Organizations using vulnerable MariaDB versions with wsrep_notify_cmd enabled may face compliance risks if this vulnerability is exploited, as it undermines the security controls required to protect regulated data.

Mitigation by upgrading to patched versions or disabling wsrep_notify_cmd is essential to maintain compliance and reduce the risk of regulatory penalties.

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Impact Analysis

This vulnerability can have severe impacts including full compromise of the affected MariaDB server. Because the vulnerability allows remote attackers to execute arbitrary shell commands without any privileges or user interaction, it can lead to complete loss of confidentiality, integrity, and availability of the database server.

• Remote code execution on the database server.
• Potential unauthorized access to sensitive data.
• Disruption or denial of database services.
• Compromise of the underlying operating system.

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Detection Guidance

Detection of this vulnerability involves checking if your MariaDB server is running a vulnerable version with the `wsrep_notify_cmd` feature enabled.

You can verify the MariaDB version by running the command: `mysql -V` or connecting to the server and running `SELECT VERSION();`.

To check if `wsrep_notify_cmd` is enabled, you can query the MariaDB configuration or run: `SHOW VARIABLES LIKE 'wsrep_notify_cmd';` within the MariaDB client.

Additionally, monitoring logs for unusual shell command executions or unexpected cluster joiner node names containing shell metacharacters may help detect exploitation attempts.

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Mitigation Strategies

The primary mitigation is to upgrade MariaDB to a fixed version: 10.6.27, 10.11.18, 11.4.12, 11.8.8, or 12.3.2 or later.

If immediate upgrade is not possible, disable the `wsrep_notify_cmd` feature to prevent execution of shell commands embedded in joiner node names.

Ensure that any cluster joiner nodes are trusted and monitor for suspicious activity related to cluster joins.

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