In this long-read post, we will be discussing CVE-2025-21499, a security vulnerability found in the MySQL Server product of Oracle MySQL. This vulnerability impacts the Data Definition Language (DDL) component of the server, and it affects versions 8.4.3 and prior as well as 9.1. and prior. The vulnerability allows a highly privileged attacker with network access via multiple protocols to compromise MySQL Server, potentially resulting in unauthorized ability to cause a hang or frequently repeatable crash (complete DoS) of the server.

According to the CVSS 3.1 scoring system, this vulnerability has a base score of 4.9, which classifies it as an availability impact. Its CVSS vector is specified as (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).

Understanding the Vulnerability

MySQL Server's DDL component is prone to a vulnerability that can be exploited by an attacker with high privileges. By exploiting this vulnerability, an attacker can cause a hang or repeatable crash of the server, leading to a complete Denial of Service (DoS) situation.

A proof-of-concept code snippet for exploiting this vulnerability could be as follows

# Python code snippet for exploiting CVE-2025-21499
import socket

target_ip = "192.168.1.10"
target_port = 3306
username = "high_privileged_user"
password = "your_password"

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((target_ip, target_port))

# Exploit code for triggering the vulnerability should be added here

s.close()

Please note that this code snippet is meant for educational purposes only and should not be used maliciously.

Here are some of the original references that discuss this vulnerability

1. https://nvd.nist.gov/vuln/detail/CVE-2025-21499
2. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-21499
3. https://www.oracle.com/security-alerts/cpuoct2024.html (section about MySQL vulnerabilities)

Exploit Details

To exploit this vulnerability, an attacker needs to have high privileges on the target MySQL Server and access to the network via multiple protocols (such as TCP/IP and UNIX domain sockets). Once the attacker achieves these conditions, they can craft and send a specially designed DDL query to the server, triggering the vulnerability and potentially causing a hang or crash of the server.

The impact of exploiting this vulnerability is severe, as it could lead to a complete denial of service situation for the target MySQL Server.

In order to mitigate the risk of this vulnerability being exploited, administrators should

1. Upgrade MySQL Server to versions beyond 8.4.3 and 9.1., as these versions contain patches for the vulnerability.

Restrict access to only trusted users with high privileges.

4. Ideally, separate high-privileged users from regular users, limiting the number of potential attackers.
5. Monitor and audit server logs for any suspicious activities, such as unauthorized access attempts or unusually high resource consumption.

Conclusion

CVE-2025-21499 is a critical vulnerability in MySQL Server that could lead to a complete denial of service situation if exploited by a highly privileged attacker. By understanding the vulnerability, its exploitation techniques, and the potential impact, organizations can take proactive steps to prevent potential attacks and ensure the security of their MySQL Server deployments.

Timeline

Published on: 01/21/2025 21:15:14 UTC
Last modified on: 01/23/2025 17:15:23 UTC