CVE-2023-22115 - Denial of Service Vulnerability in Oracle MySQL Server (DML Component)

MySQL is one of the most popular open-source relational database management systems. Still, even widely adopted software can harbor vulnerabilities, and CVE-2023-22115 is a reminder of that. This post will walk you through what this vulnerability is, why it matters, and, in simple terms, how it can be triggered and potentially exploited.

What is CVE-2023-22115?

CVE-2023-22115 is a vulnerability discovered in the MySQL Server product of Oracle. Specifically, it lies in the DML (Data Manipulation Language) component that handles SQL operations like INSERT, UPDATE, and DELETE.

CVSS 3.1 Base Score: 4.9 (Availability impact only)

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

What Does This Mean?

- Easily exploitable: An attacker only needs valid (high privilege) credentials and network access—no social engineering or complex pre-conditions.
- Attack Impact: A successful attack can either hang the MySQL server or cause it to crash repeatedly. This results in a Denial of Service (DoS) where the database is unavailable to legitimate users.
- No Data Theft: This vulnerability does not allow attackers to steal or modify data, only to make the server unavailable.

Who Can Exploit It?

The exploit requires high-privileged credentials (e.g., a user with advanced data access rights). That means a regular, unauthenticated user cannot exploit CVE-2023-22115—it's more likely an insider threat or someone who has already compromised user credentials.

How Does it Work?

Without going too deep into MySQL’s internals, the bug is found in the handling of DML statements. Crafted SQL queries involving certain data types or sequences of operations can trigger a server crash.

Here is a simplified example, inspired by community discussion:

Here’s a typical way someone might cause a crash based on publicly available descriptions

-- Assume attacker has ALL PRIVILEGES on the targeted database:

-- Step 1: Create a table with a JSON column (the vulnerability involves DML+JSON):
CREATE TABLE crash_test (
  id INT PRIMARY KEY AUTO_INCREMENT,
  data JSON
);

-- Step 2: Insert deliberately invalid JSON or payload that triggers a bug:
INSERT INTO crash_test (data) VALUES (CAST('{"key":null}' AS JSON));

-- Step 3: Run complex DML that manipulates JSON structures in a certain way:
UPDATE crash_test
SET data = JSON_SET(data, '$.key', '{"nested": [1,2,3, {"trigger_bug": true}]}')
WHERE id = 1;

-- Depending on the underlying bug, this (or similar complex JSON operations)
-- can crash or hang the MySQL server process.

> Note: The actual malicious query may change depending on the MySQL build and the way JSON processing is implemented. Attackers can iterate on this style of input until they find the crash-inducing edge case, using only standard SQL features.

Mitigation & Remediation

Oracle patched this vulnerability in MySQL 8..34 (July 2023). You should upgrade as soon as possible.

- Download latest MySQL release: https://dev.mysql.com/downloads/mysql/
- Patch notes for CVE-2023-22115: https://www.oracle.com/security-alerts/cpujul2023.html

Monitor for unusual DML or repeated server crashes in your logs.

- Optionally, configure MySQL to alert on and limit connections from the same user/IP to blunt brute-force attempts.

References

- NVD entry for CVE-2023-22115
- Oracle MySQL Critical Patch Update Advisory – July 2023
- MySQL Release Notes
- Reporting Security Vulnerabilities in MySQL

Conclusion

CVE-2023-22115 isn’t the most dangerous bug out there—you need high privileges and can only crash the server, not steal data. But the risk of a simple, repeated DoS against critical production systems should not be ignored.

If you run MySQL 8..33 or earlier, upgrade immediately. Monitor your server for unexpected restarts, and remember: even edge-case vulnerabilities like this are worth patching, especially in environments where insider threats or compromised credentials are possible.

Timeline

Published on: 10/17/2023 22:15:00 UTC
Last modified on: 10/18/2023 18:19:00 UTC