If you use MySQL as your primary database engine, it’s critical to keep up with security updates and CVE disclosures. One vulnerability that caught the attention of database administrators is CVE-2022-21451. Let's break down what it is, how it can be exploited, and what you need to do.

What is CVE-2022-21451?

CVE-2022-21451 is a vulnerability affecting Oracle MySQL Server, specifically in the InnoDB storage engine component. This bug is present in all supported versions up to and including 5.7.37 and 8..28.

This vulnerability is classified as "Difficult to exploit", meaning it’s not easy for just anyone to take advantage of it. However, a high-privileged user (like a DBA or someone with broad access) could use it to crash your MySQL server—disrupting your apps and website. This type of attack is called a Denial of Service (DoS). This bug does not directly leak or alter your data, but it can make your database completely unavailable.

CVSS 3.1 Base Score: 4.4 (Moderate risk, due to availability impact)

- Vector: (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H)

Translation:

MySQL 5.7.37 and earlier

If you're running these or anything older, you’re at risk if you give access to trusted users or automation.

How Does the Exploit Work?

While Oracle didn’t disclose all the technical details, security researchers and patch changelogs hint that the bug exists in how InnoDB processes certain internal operations.

A high-privileged attacker (for example, a user with SUPER or PROCESS rights) can send a specially crafted set of queries over the network that will trigger memory handling or logic errors in InnoDB, causing the whole MySQL daemon (mysqld) to hang or crash.

Example Attack Scenario (Pseudocode)

Let’s walk through a simplified code snippet that reflects how an attacker might exploit such a vulnerability:

-- Assume attacker has high privileges.
-- Simulate complex/invalid operations to stress InnoDB:

START TRANSACTION;

-- Repeatedly create and drop tables to trigger resource/desync issues
CREATE TABLE t1 (id INT PRIMARY KEY);
DROP TABLE t1;
CREATE TABLE t1 (id INT PRIMARY KEY);
DROP TABLE t1;

-- Deliberately use an unsupported or faulty feature
ALTER TABLE t1 DISCARD TABLESPACE;

-- Insert massive transaction loads or conflicting operations
INSERT INTO t1 VALUES (1), (2), (3);    -- Table t1 may not exist at this point

-- Commit or rollback
COMMIT;

MySQL server may fatally crash or hang, denying all service until it’s restarted by an admin.

*Note:* The actual exploit may require more precise triggers. Often, public proof-of-concept code won’t be released for such bugs. The above snippet demonstrates the concept.

Real-World Impact

- Anyone with high-level credentials *inside your company or cloud* (or through an application bug) could bring down your MySQL server.

No data leakage or manipulation, but system availability is lost.

- Since the bug needs high privileges, it limits exposure, but large teams, complex apps, or shared servers are still at risk.

Upgrade to MySQL 5.7.38+ or 8..29+

- Oracle’s official fix: Oracle Critical Patch Update Advisory - April 2022

References

- NVD Entry for CVE-2022-21451
- Oracle's Security Alert (see MySQL section)
- MySQL Release Notes 8..29
- MySQL Release Notes 5.7.38

Summary

CVE-2022-21451 shows how even trusted insiders with too much access can accidentally or intentionally crash crucial systems. If you run MySQL, make sure your system is patched and keep a close eye on who has high-level access.

Don’t let your database fall to an easy DoS—update today.

*This post was created exclusively for this session, blending public data, patch release notes, and synthesized insights to help you defend your infrastructure.*

Timeline

Published on: 04/19/2022 21:15:00 UTC
Last modified on: 05/02/2022 13:31:00 UTC