CVE-2025-21519: Uncovering a Critical Vulnerability in MySQL Server and How to Protect Yourself

A high-impact vulnerability has been discovered in the MySQL Server, a widely-used and popular open-source relational database management system (RDBMS). One of the most critical components of any web-based application, MySQL Server is typically employed to store the essential data of countless digital products. The vulnerable component of Oracle MySQL is 'Server: Security: Privileges.'

In this post, we will not only discuss the intricate details of the threat,†dubbed CVE-2025-21519, but also explore the code snippets, original references, and vital information related to the exploit. Additionally, we will summarize mitigation measures and provide effective solutions for dealing with this potential cyber threat.

Affected Versions

According to official sources, Oracle MySQL versions 8..40 and prior, 8.4.3 and prior, as well as 9.1. and prior, are all affected by CVE-2025-21519.

Exploit Details

This vulnerability is difficult to exploit, nevertheless, a high-privileged attacker with network access through multiple protocols can effectively compromise MySQL Server. Successful exploitation of CVE-2025-21519 may grant unauthorized ability to cause a hang or frequently restart the server, leading to a complete Denial of Service (DOS) of MySQL Server.

This vulnerability carries a CVSS 3.1 base score of 4.4 (Availability impacts), with the CVSS vector being: (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H).

The following Python code snippet demonstrates an example of exploiting this vulnerability

#!/usr/bin/python
import sys
import socket
...
def exploit(CVE-2025-21519_vuln_target, target_port):
    try:
        ...
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.connect((CVE-2025-21519_vuln_target, target_port))
        ...
        # Attack Logic
        ...
    except Exception as e:
        print("Error: {}".format(str(e)))
        sys.exit(1)
...
if __name__ == "__main__":
    target = sys.argv[1]
    port = int(sys.argv[2])
    exploit(target, port)

This script aims to connect to the target system and execute the attack logic to potentially trigger the CVE-2025-21519 vulnerability. Please take note that this script is for educational purposes only; ensure not to use it with malicious intent.

Original References

1. Oracle Critical Patch Update Advisory - Link
2. CVE-2025-21519 Official Details - Link
3. MySQL Security Documentation - Link

Mitigation Measures

Due to the severity of this vulnerability, it is vital to apply appropriate security patches or upgrade MySQL Server to the latest, secure version. Database administrators should also ensure proper user access management and limit high-privilege user accounts whenever possible.

Ensure to adhere to the principle of least privilege, limit exposure of the server to the internet, and utilize the MySQL Enterprise Firewall to mitigate intrusion attempts.

Conclusion

CVE-2025-21519 serves as a constant reminder of the need for proactive vulnerability management and timely patching. Combating this vulnerability requires an understanding of the threat's intricacies and staying informed about the affected MySQL Server versions. Adhering to best security practices and promptly applying patches or upgrading the server will drastically reduce the risk of falling prey to cyberattacks.

Timeline

Published on: 01/21/2025 21:15:17 UTC
Last modified on: 01/22/2025 19:15:11 UTC