CVE-2025-30682: Oracle MySQL Server DOS Vulnerability

CVE-2025-30682 Overview

CVE-2025-30682 is a denial-of-service vulnerability in the Oracle MySQL Server Optimizer component. The flaw allows a low-privileged attacker with network access via multiple protocols to trigger a hang or a frequently repeatable crash of the MySQL Server process, resulting in complete loss of database availability. Oracle disclosed the issue in the April 2025 Critical Patch Update. The weakness is classified under [CWE-732: Incorrect Permission Assignment for Critical Resource].

Critical Impact
An authenticated attacker can remotely crash or hang Oracle MySQL Server instances, producing a complete denial of service against affected databases.

Affected Products

Oracle MySQL Server 8.0.0 through 8.0.41
Oracle MySQL Server 8.4.0 through 8.4.4
Oracle MySQL Server 9.0.0 through 9.2.0

Discovery Timeline

2025-04-15 - Oracle publishes the April 2025 Critical Patch Update including CVE-2025-30682
2025-04-15 - CVE-2025-30682 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-30682

Vulnerability Analysis

The vulnerability resides in the Optimizer component of Oracle MySQL Server. The Optimizer is responsible for translating SQL statements into efficient execution plans. A specifically crafted query causes the optimizer to enter a state that either hangs the server or triggers a repeatable crash of the database process.

Exploitation requires only low privileges, meaning any authenticated database account with basic query capabilities can trigger the condition. The attack is delivered over the network using MySQL's supported protocols, and Oracle rates the attack complexity as low. Successful exploitation impacts only availability; confidentiality and integrity of stored data are not affected.

Because many application architectures grant a shared low-privileged database account to application tiers, a compromised web application or a malicious internal user with query access can knock production databases offline.

Root Cause

Oracle has not published detailed technical root-cause information beyond the Oracle Critical Patch Update April 2025 advisory. The [CWE-732] mapping indicates that improper permission assignment on a critical resource contributes to the flaw within the query optimization path.

Attack Vector

The attacker requires network reachability to the MySQL Server listener and valid low-privileged credentials. Once authenticated, the attacker submits a specifically crafted SQL statement that reaches the vulnerable optimizer logic. The server then either hangs or crashes, denying service to legitimate clients. No user interaction is required.

No verified public proof-of-concept is available. The vulnerability is described in prose only; refer to the NetApp Security Advisory NTAP-20250502-0006 for downstream product impact.

Detection Methods for CVE-2025-30682

Indicators of Compromise

Unexpected mysqld process crashes or restarts recorded in error.log with stack traces referencing optimizer functions.
Client connections reporting Lost connection to MySQL server during query immediately after complex or unusual queries.
Sustained CPU spikes on the MySQL host followed by unresponsiveness of the server listener.
Repeated failed query executions from a single low-privileged account preceding a crash event.

Detection Strategies

Monitor MySQL error.log and systemd journal entries for repeated abnormal termination or signal-based shutdowns of mysqld.
Enable and review the MySQL general or audit log for anomalous query patterns originating from application service accounts.
Correlate database availability alerts with authentication events to identify the source account executing the triggering query.

Monitoring Recommendations

Baseline normal query performance and alert on queries that consistently precede optimizer stalls or connection drops.
Track mysqld uptime and restart counts as a service-level indicator and route deviations to the SOC.
Forward MySQL logs to a centralized analytics platform to enable cross-host correlation and historical review.

How to Mitigate CVE-2025-30682

Immediate Actions Required

Apply the fixes from the Oracle Critical Patch Update April 2025 to all affected MySQL Server 8.0.x, 8.4.x, and 9.x instances.
Inventory MySQL deployments, including embedded instances in third-party products such as those covered by the NetApp advisory.
Restrict network reachability to the MySQL listener so only authorized application hosts and administrators can connect.
Review database account privileges and remove unused low-privileged accounts that could be leveraged to trigger the flaw.

Patch Information

Oracle addressed CVE-2025-30682 in the April 2025 Critical Patch Update. Upgrade MySQL Server to the fixed release above 8.0.41 for the 8.0 branch, above 8.4.4 for the 8.4 LTS branch, or above 9.2.0 for the innovation branch. Consult the Oracle Critical Patch Update April 2025 matrix for the exact fixed versions applicable to each supported release train.

Workarounds

Enforce least-privilege on application database accounts, granting only the specific schemas and statements each service requires.
Place MySQL Server behind a database firewall or proxy that can rate-limit or block anomalous query patterns.
Restrict inbound access to the MySQL port using host firewalls and network ACLs, allowing only known application tiers.
Implement automatic service recovery so mysqld restarts quickly if crashed, reducing outage duration while patching is scheduled.

bash

# Configuration example: restrict MySQL network exposure and enable auto-restart
# /etc/mysql/mysql.conf.d/mysqld.cnf
[mysqld]
bind-address = 10.0.0.10        # bind only to internal management interface
skip-name-resolve = ON
max_connections = 200

# systemd override to auto-restart mysqld on crash
# /etc/systemd/system/mysql.service.d/override.conf
[Service]
Restart=always
RestartSec=5s