CVE-2025-50085: Oracle MySQL Server InnoDB DOS Vulnerability

CVE-2025-50085 Overview

CVE-2025-50085 is an authorization vulnerability [CWE-863] in the InnoDB storage engine of Oracle MySQL Server. A high-privileged attacker with network access can exploit the flaw through multiple MySQL protocols. Successful exploitation causes a hang or repeatable crash of the MySQL Server process, resulting in a complete denial of service. The flaw also permits unauthorized update, insert, or delete operations against a subset of server-accessible data. Oracle disclosed the issue in the July 2025 Critical Patch Update. Affected releases include MySQL Server 8.0.0 through 8.0.42, 8.4.0 through 8.4.5, and 9.0.0 through 9.3.0.

Critical Impact
Authenticated attackers can crash MySQL Server and tamper with accessible data, disrupting database-backed applications and compromising data integrity.

Affected Products

Oracle MySQL Server 8.0.0 through 8.0.42
Oracle MySQL Server 8.4.0 through 8.4.5
Oracle MySQL Server 9.0.0 through 9.3.0

Discovery Timeline

2025-07-15 - CVE-2025-50085 published to the National Vulnerability Database
2025-07-15 - Oracle releases fix in the July 2025 Critical Patch Update
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-50085

Vulnerability Analysis

The vulnerability resides in the InnoDB storage engine, the default transactional engine for MySQL Server. InnoDB handles row-level locking, multi-version concurrency control, and crash recovery for most production MySQL deployments. The flaw is classified as an incorrect authorization issue [CWE-863], meaning the server fails to properly enforce privilege checks for certain operations. An attacker with high privileges on the server can trigger conditions that cause the database process to hang or crash repeatedly, producing a complete denial of service. The same code path also allows the attacker to modify data they should not be permitted to change. Because the attack is network-based and works across multiple MySQL protocols, exposed database instances with over-provisioned accounts are at elevated risk.

Root Cause

The root cause is improper authorization enforcement within the InnoDB component. Privilege validation for specific operations does not match the intended access control model, allowing authorized sessions to perform actions beyond their granted scope. The same deficiency triggers an unstable server state that leads to process hangs or crashes.

Attack Vector

Exploitation requires an authenticated session with high privileges and network reachability to the MySQL Server. The attacker interacts with the server over one of the supported MySQL protocols and issues the crafted request against InnoDB. No user interaction is required, and the attack complexity is low once the preconditions are met.

No verified public exploit code is available for CVE-2025-50085. See the Oracle Security Alert - July 2025 for vendor technical details.

Detection Methods for CVE-2025-50085

Indicators of Compromise

Unexpected mysqld process crashes or hangs followed by automatic restarts by systemd or mysqld_safe.
InnoDB assertion failures or stack traces in the MySQL error log near the time of the disruption.
Unexplained UPDATE, INSERT, or DELETE statements in the binary log originating from administrative accounts.
Repeated connections from a single high-privileged account preceding server instability.

Detection Strategies

Enable the MySQL general query log or audit plugin to capture statements executed by privileged accounts and review them for anomalous data modifications.
Monitor the MySQL error log for recurring InnoDB-related crashes and correlate with session identifiers from performance_schema.
Alert on mysqld process exits and restarts through host-based telemetry.

Monitoring Recommendations

Baseline normal query patterns for administrative accounts and alert on deviations.
Track MySQL server uptime and crash frequency as a service-health signal.
Correlate database audit events with network flow data to identify unexpected sources connecting with high-privileged credentials.

How to Mitigate CVE-2025-50085

Immediate Actions Required

Apply the July 2025 Critical Patch Update from Oracle to all affected MySQL Server instances.
Inventory MySQL deployments and identify versions in the vulnerable ranges 8.0.0-8.0.42, 8.4.0-8.4.5, and 9.0.0-9.3.0.
Audit accounts holding administrative privileges and revoke those that are not strictly required.
Restrict network exposure of MySQL Server to trusted application subnets using firewall or security group rules.

Patch Information

Oracle addressed CVE-2025-50085 in the July 2025 Critical Patch Update. Upgrade to MySQL Server 8.0.43, 8.4.6, 9.4.0, or later as applicable. Refer to the Oracle Security Alert - July 2025 for the complete patch matrix and download locations.

Workarounds

Enforce least-privilege on all MySQL accounts, limiting SUPER, PROCESS, and schema-wide ALTER or DROP grants.
Place MySQL Server behind a bastion or private network segment to prevent direct network reachability from untrusted zones.
Require strong authentication and rotate credentials for privileged database accounts.
Enable binary logging to support forensic reconstruction of any unauthorized data modifications.

bash

# Verify installed MySQL Server version against the fixed releases
mysql --version
mysql -u root -p -e "SELECT VERSION();"

# Review currently granted high privileges
mysql -u root -p -e "SELECT user, host FROM mysql.user WHERE Super_priv='Y' OR Process_priv='Y';"