Oracle MySQL is one of the most used database management systems across the globe. But recently, a new vulnerability identified as CVE-2025-30722 has been disclosed, affecting the mysqldump component of the MySQL Client. If your systems use versions 8..-8..41, 8.4.-8.4.4, or 9..-9.2., your data may be at risk—even though exploiting this vulnerability is tough, especially for attackers with limited access.

In this article, you’ll get an easy-to-understand explanation of what CVE-2025-30722 is, how an attacker could use it, and what you should do to stay safe.

What is CVE-2025-30722?

CVE-2025-30722 is a security vulnerability in the mysqldump component of the Oracle MySQL Client. This is the tool many admins use to export and back up their data. The bug allows a low-privileged attacker, if they have network access and a bit of luck, to gain unauthorized access to sensitive database information and possibly change or delete some of it.

9.. - 9.2.

For more, see Oracle’s own advisory:
Oracle Critical Patch Update Advisory - July 2024 (search for CVE-2025-30722).

How the mysqldump Vulnerability Works

mysqldump exports your MySQL database by connecting to your server and dumping the data as SQL. Internally, mysqldump parses responses from the server and reconstructs database objects. CVE-2025-30722 is about a flaw in *how mysqldump parses certain special cases*—where a *malicious MySQL server*, or a *fake server on the network*, can send specially-crafted responses to the client.

This could let an attacker

- Steal sensitive data from the mysqldump user (even if only some data is exposed, it could be the critical stuff)

Bypass some access controls the victim expects

Key Point: While the attacker must have some access, it does _not_ require full administrator or root access. This makes it more dangerous in complex environments.

Here’s how an attacker might use this in the real world

1. The attacker can intercept or spoof your mysqldump connection (for example, through DNS poisoning, MITM, or by hosting a malicious MySQL server).

You (the victim) run mysqldump to back up your data.

3. The attacker's server sends back malicious data in response, triggering the flaw inside the mysqldump code.

Code Walkthrough: What Might the Vulnerable Code Look Like?

While Oracle does not publish the vulnerability’s code for obvious safety reasons, here’s a simplified illustration of what happens:

// This is a made-up, simplified example mimicking typical export logic
MYSQL_RES* res = mysql_list_tables(mysql, dbname);
while ((row = mysql_fetch_row(res))) {
    // Attacker can craft row data to contain malicious content
    // Vulnerable mysqldump code fails to sanitize or check it
    fprintf(output, "CREATE TABLE %s ...;\n", row[]);
    /* ... */
}

A malicious MySQL server could return unexpected or malformed struct row[] data, which the client just writes to the dump file. This may expose data or allow manipulation of the output.

Proof-of-Concept: (Educational Only)

Suppose you’re a pen tester or admin. You might set up a *fake* MySQL server using mysql-fake-server or a custom script to behave maliciously.

Python Example:
(PyMySQL must be installed)

import socket

def fake_mysql_server():
    s = socket.socket()
    s.bind(('...', 3306))
    s.listen(1)
    print("Fake MySQL server running on port 3306...")
    client, addr = s.accept()
    
    # Send a crafted handshake, then a crafted response
    # that triggers the bug in the client...
    # (for real testing, you'd need the exact protocol bytes)

fake_mysql_server()

Then, you run

mysqldump -h FAKE_HOST -u user -p dbname

And observe how mysqldump processes malicious responses.

Disclaimer: This is a simplified demonstration. Do _not_ attack systems you don't own.

How to Protect Yourself

1. Patch immediately: Oracle has released updates to fix this issue. Upgrade to the latest MySQL version.
2. Restrict network access: Make sure only trusted hosts can connect to your MySQL servers—never use mysqldump over an insecure or untrusted network.
3. Monitor for unusual dumps: If you see an unexpectedly large or modified dump file, suspect something’s wrong.
4. Encrypt your connections: Always use TLS/SSL for MySQL clients, especially for backups.

References

- Oracle CPU Advisory - July 2024
- NVD Entry for CVE-2025-30722 (*link may become active later*)
- How mysqldump Works
- General advice on fake MySQL servers

Conclusion

CVE-2025-30722 is a subtle but real risk for anyone using Oracle MySQL’s mysqldump. Even though it’s “hard to exploit,” determined attackers with some network access can use it to leak or modify data in surprising ways. If you manage MySQL servers, prioritize this patch and review your network security practices.

Stay patched. Stay alert. Protect your data.

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Timeline

Published on: 04/15/2025 21:16:01 UTC
Last modified on: 04/19/2025 01:15:45 UTC