CVE-2025-21546

What it actually does

High-privileged network attacker can bypass privilege checks to perform unauthorized data modifications (insert/update/delete) and limited reads within the MySQL Server.

Why it matters to the business

Privileged insiders or compromised accounts can alter or view subsets of database content without proper authorization, increasing risk of data tampering or leakage in production environments.

How an attack unfolds

An attacker with high privileges and network access authenticates to the MySQL Server over supported protocols and issues crafted queries that exploit insufficient privilege enforcement in the security component, resulting in unauthorized data changes and reads.

How to fix it

Upgrade affected MySQL Server installations to versions beyond 8.0.40, 8.4.3, and 9.1.0. Apply the corresponding fixed package versions for any downstream components such as libhibernate3-java on Ubuntu 16.04/18.04/20.04 as listed in the advisory.

How to confirm the fix worked

Verify MySQL Server version is newer than the affected releases, review privilege grants and audit logs for unexpected data modifications, and confirm no unauthorized access patterns remain after patching.

Typical attack path

1. Obtain high-privileged database credentials
2. Establish network connection to MySQL Server via supported protocols
3. Issue queries that trigger the privilege bypass in the security component
4. Perform unauthorized inserts, updates, deletes, or reads on accessible data

How to detect it

Examine database audit logs and query logs for unexpected privilege escalations or data modifications by high-privileged accounts; correlate with network connection records from the affected MySQL Server.

What your security team should do

• Prioritize patching MySQL Server instances to fixed versions immediately given the network-accessible nature
• Review and tighten high-privileged account permissions and network exposure
• Enable enhanced auditing on privilege-related operations
• Monitor for any post-patch anomalies in data access patterns