CVE-2026-22002: Oracle MySQL Server DoS Vulnerability

CVE-2026-22002 Overview

CVE-2026-22002 is a Denial of Service vulnerability affecting the Server: Optimizer component of Oracle MySQL Server. This vulnerability allows a high-privileged attacker with network access to cause a complete denial of service condition, resulting in a hang or frequently repeatable crash of the MySQL Server. The vulnerability is classified as easily exploitable and affects multiple major version branches of MySQL Server.

Critical Impact

Successful exploitation enables complete denial of service of MySQL Server instances, potentially causing significant business disruption for organizations relying on MySQL databases for critical operations.

Affected Products

• Oracle MySQL Server 8.0.0 through 8.0.45
• Oracle MySQL Server 8.4.0 through 8.4.8
• Oracle MySQL Server 9.0.0 through 9.6.0

Discovery Timeline

• April 21, 2026 - CVE-2026-22002 published to NVD
• April 23, 2026 - Last updated in NVD database

Technical Details for CVE-2026-22002

Vulnerability Analysis

This vulnerability resides in the Server: Optimizer component of Oracle MySQL Server. The Optimizer is responsible for determining the most efficient execution plan for SQL queries, making it a critical component of database performance. The flaw is categorized as CWE-400 (Uncontrolled Resource Consumption), indicating that the vulnerability allows an attacker to consume excessive server resources.

The vulnerability requires high privileges to exploit, meaning the attacker must have an authenticated session with elevated database permissions. However, once these prerequisites are met, the attack can be executed with low complexity over the network via multiple protocols supported by MySQL.

Root Cause

The root cause of CVE-2026-22002 is uncontrolled resource consumption (CWE-400) within the MySQL Server Optimizer component. The Optimizer fails to properly limit or manage resource allocation when processing certain malformed or specially crafted queries, allowing an authenticated attacker with high privileges to trigger resource exhaustion conditions that lead to service unavailability.

Attack Vector

The attack vector is network-based, requiring the attacker to have authenticated network access to the MySQL Server with high-level privileges. The attacker can exploit this vulnerability by sending specially crafted queries that trigger the vulnerable code path in the Optimizer component. The attack does not require user interaction and affects only the availability of the system, with no impact on confidentiality or integrity.

The vulnerability can be exploited via multiple network protocols supported by MySQL Server, including the native MySQL protocol. An attacker with sufficient database privileges (such as a compromised administrative account or a malicious insider) can repeatedly trigger the crash condition, effectively denying service to legitimate users.

Detection Methods for CVE-2026-22002

Indicators of Compromise

• Unexpected MySQL Server crashes or hangs with optimizer-related error messages in logs
• Abnormal patterns of complex queries from high-privileged database accounts
• Repeated service restarts of MySQL daemon without apparent cause
• High CPU or memory utilization preceding server crashes

Detection Strategies

• Monitor MySQL error logs for optimizer-related crash messages and assertion failures
• Implement query logging and analysis for unusual query patterns from privileged accounts
• Deploy database activity monitoring solutions to detect anomalous administrative behavior
• Configure alerting on MySQL service restarts and availability gaps

Monitoring Recommendations

• Enable MySQL's general query log or slow query log to capture problematic queries for forensic analysis
• Implement real-time monitoring of MySQL Server process health and resource consumption
• Configure threshold-based alerts for repeated service crashes within short time windows
• Review audit logs for suspicious activities from high-privileged database accounts

How to Mitigate CVE-2026-22002

Immediate Actions Required

• Apply the Oracle security patches from the April 2026 Critical Patch Update immediately
• Audit and restrict high-privilege database accounts to only those users with legitimate need
• Review and limit network access to MySQL Server instances using firewall rules
• Implement monitoring for MySQL Server availability and crash events

Patch Information

Oracle has released patches addressing this vulnerability in the Oracle Critical Patch Update Advisory - April 2026. Organizations should upgrade to the following patched versions:

• MySQL Server 8.0.46 or later for the 8.0.x branch
• MySQL Server 8.4.9 or later for the 8.4.x branch
• MySQL Server 9.6.1 or later for the 9.x branch

Refer to the official Oracle security advisory for detailed patch instructions and download links.

Workarounds

• Restrict network access to MySQL Server to trusted hosts and networks only
• Implement strict privilege management to minimize the number of high-privileged accounts
• Deploy database activity monitoring to detect and block suspicious query patterns
• Consider using MySQL proxy solutions to filter potentially malicious queries before they reach the server

# Example: Restrict MySQL access to specific trusted networks
# Add to my.cnf or mysql.conf.d configuration
[mysqld]
bind-address = 127.0.0.1
# For specific network access, use firewall rules instead

# Example: Review users with high privileges
# Run in MySQL client to audit privileged accounts
# SELECT user, host FROM mysql.user WHERE Super_priv = 'Y';