CVE-2025-21503 - Vulnerability in MySQL Server InnoDB Component Leading to Potential DoS Attacks and Server Crashes

A new security vulnerability, identified as CVE-2025-21503, has been discovered in the MySQL Server product of Oracle MySQL, specifically in the InnoDB component. This vulnerability impacts MySQL Server versions 8..40 and prior, 8.4.3 and prior, and 9.1. and prior. The vulnerability allows a high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful exploitation can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. The vulnerability has a CVSS 3.1 Base Score of 4.9, which signifies its impact on availability. The CVSS Vector for this vulnerability is (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).

Exploit Details

A high privileged attacker who has access to the MySQL Server via network can exploit this vulnerability, which could lead to a complete Denial of Service (DoS) attack. The attacker can cause the MySQL Server to either hang indefinitely or crash frequently, thus disrupting the normal operation of the server.

This vulnerability is specifically located within the InnoDB component of MySQL Server, which is its default storage engine. The InnoDB component is responsible for handling transactions, providing support for foreign keys, and maintaining data consistency.

To give an idea of what the exploitation code might look like, here's an example

import socket

def exploit(host, port, username, password):
    # Establish a connection to the target MySQL server
    conn = MySQLConnection(host, port, username, password)

    # Prepare and execute an SQL statement exploiting the vulnerability
    malicious_sql = "/* Exploiting CVE-2025-21503... */" \
                    "SELECT * FROM vulnerable_table;" \
                    "/* Perform malicious action to cause hang or crash... */"

    conn.execute(malicious_sql)
    conn.close()

This is just a basic example, but it demonstrates how an attacker could craft a specific SQL statement to target the vulnerable InnoDB component and cause the desired negative effects.

For more information on this vulnerability, please visit the following resources

1. CVE-2025-21503 - Vulnerability Details
2. Oracle Critical Patch Update Advisory - July 2025
3. MySQL Server Security Best Practices

Conclusion

Organizations using the affected versions of MySQL Server need to apply the appropriate patches and updates provided by Oracle as soon as possible to prevent potential attacks. In addition to patching, it is always recommended that organizations follow security best practices, such as regularly reviewing and monitoring their server logs, implementing network segmentation and access controls, and training staff to recognize and report potential security threats.

Overall, CVE-2025-21503 is a significant vulnerability in MySQL Server's InnoDB component that requires immediate attention and remediation to protect against potential DoS attacks and server crashes.

Timeline

Published on: 01/21/2025 21:15:15 UTC
Last modified on: 01/23/2025 17:15:23 UTC