CVE-2025-53044: Oracle MySQL Server InnoDB DOS Vulnerability

CVE-2025-53044 Overview

CVE-2025-53044 is a denial-of-service vulnerability in the InnoDB storage engine of Oracle MySQL Server. Oracle disclosed the flaw in the October 2025 Critical Patch Update. A high-privileged attacker with network access can exploit the issue over multiple protocols to trigger a hang or repeatable crash of the MySQL Server process. The weakness is classified under CWE-400 (Uncontrolled Resource Consumption). Successful exploitation results in complete availability loss for database workloads dependent on the affected instance, without impact to confidentiality or integrity.

Critical Impact
Authenticated attackers can trigger a full denial of service against Oracle MySQL Server, halting all dependent applications until the service is restarted.

Affected Products

Oracle MySQL Server versions 8.0.0 through 8.0.43
Oracle MySQL Server versions 8.4.0 through 8.4.6
Oracle MySQL Server versions 9.0.0 through 9.4.0

Discovery Timeline

2025-10-21 - CVE-2025-53044 published to NVD as part of Oracle's October 2025 Critical Patch Update
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-53044

Vulnerability Analysis

The vulnerability resides in the InnoDB storage engine, MySQL's default transactional engine responsible for row-level locking, buffer pool management, and crash recovery. An authenticated attacker with elevated database privileges can submit crafted requests over supported MySQL network protocols to induce a resource-exhaustion condition. The condition drives the server into an unresponsive state or forces a repeatable crash of the mysqld process.

Because exploitation requires only network reachability and existing high-privileged credentials, any compromised administrator, DBA service account, or replication user can weaponize the flaw. The impact is limited to availability, but repeated crashes can corrupt in-flight transactions and delay recovery through InnoDB redo log replay.

Root Cause

The issue is a resource-consumption weakness ([CWE-400]) within InnoDB request handling. The engine fails to bound processing of specific inputs, allowing an attacker to consume server resources or reach an invalid internal state that terminates the process. Oracle has not publicly detailed the specific code path.

Attack Vector

Exploitation occurs over the network through any MySQL-supported protocol reaching an authenticated session. The attacker must already hold high-level database privileges. No user interaction is required, and the attack complexity is low. Repeated invocation reliably reproduces the crash, enabling sustained denial of service against production database clusters.

Refer to the Oracle Security Alert October 2025 for authoritative technical context.

Detection Methods for CVE-2025-53044

Indicators of Compromise

Unexpected mysqld process termination or restart events in system logs and mysqld.err
InnoDB assertion failures, stack traces, or [ERROR] [MY-*] entries preceding shutdown
Repeated connection resets or query timeouts from a single authenticated session
Sudden spikes in InnoDB buffer pool, undo log, or thread activity tied to one user account

Detection Strategies

Correlate MySQL error log crash signatures with the source IP and account of the last executed statement.
Enable the MySQL general query log or audit plugin on sensitive instances to capture pre-crash statements.
Alert on mysqld restart frequency exceeding baseline through host monitoring or systemd journal watchers.
Review privileged account activity for unusual protocol usage such as X Protocol or replication channels.

Monitoring Recommendations

Track availability metrics such as MySQL uptime, connection errors, and replication lag through your observability stack.
Forward MySQL error logs and audit events to a centralized SIEM for cross-host correlation.
Monitor privileged account authentications and flag logins from unexpected network segments.
Baseline query patterns for administrative accounts and alert on deviations that precede service restarts.

How to Mitigate CVE-2025-53044

Immediate Actions Required

Apply the Oracle October 2025 Critical Patch Update to all affected MySQL Server 8.0, 8.4, and 9.x instances.
Inventory database accounts holding administrative or replication privileges and rotate credentials suspected of exposure.
Restrict network access to MySQL listener ports using firewall rules or security groups, permitting only known application hosts.
Enable audit logging on production instances to preserve forensic evidence of pre-crash activity.

Patch Information

Oracle addressed CVE-2025-53044 in the October 2025 Critical Patch Update. Upgrade MySQL Server 8.0 to a release later than 8.0.43, MySQL Server 8.4 to a release later than 8.4.6, and MySQL Server 9.x to a release later than 9.4.0. See the Oracle Security Alert October 2025 for the complete patch matrix and download instructions.

Workarounds

Enforce least privilege by revoking SUPER, SYSTEM_VARIABLES_ADMIN, and similar high-tier privileges from accounts that do not require them.
Place MySQL instances behind bastion hosts or private subnets to limit network reachability to trusted administrators.
Configure connection rate limits and per-user resource controls with MAX_USER_CONNECTIONS and MAX_QUERIES_PER_HOUR.
Deploy high-availability topologies such as InnoDB Cluster or Group Replication to reduce downtime if a node is crashed.

bash

# Configuration example: restrict privileged access and cap per-user resources
REVOKE SUPER, SYSTEM_VARIABLES_ADMIN ON *.* FROM 'app_user'@'%';
ALTER USER 'app_user'@'%' WITH MAX_USER_CONNECTIONS 20 MAX_QUERIES_PER_HOUR 5000;
FLUSH PRIVILEGES;