CVE-2025-21577
📋 TL;DR
This vulnerability in MySQL Server's InnoDB component allows authenticated attackers with low privileges to cause a denial of service (DoS) by crashing or hanging the database server. It affects MySQL versions 8.0.0-8.0.41, 8.4.0-8.4.4, and 9.0.0-9.2.0. Attackers need network access and valid credentials to exploit this vulnerability.
💻 Affected Systems
- Oracle MySQL Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete unavailability of MySQL database service, disrupting all applications dependent on the database.
Likely Case
Service disruption causing application downtime until MySQL is restarted.
If Mitigated
Limited impact with proper network segmentation and privilege restrictions.
🎯 Exploit Status
Oracle rates this as 'Easily exploitable' requiring only low privileges and network access via multiple protocols.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply Critical Patch Update for April 2025 or later
Vendor Advisory: https://www.oracle.com/security-alerts/cpuapr2025.html
Restart Required: Yes
Instructions:
1. Download the appropriate Critical Patch Update from Oracle. 2. Apply the patch following Oracle's MySQL update procedures. 3. Restart the MySQL service to apply changes.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict network access to MySQL servers to only trusted hosts and applications.
# In MySQL configuration (my.cnf): bind-address = 127.0.0.1
# Or use firewall: sudo ufw deny 3306/tcp
Privilege Minimization
allApply principle of least privilege to database users, removing unnecessary permissions.
REVOKE ALL PRIVILEGES ON *.* FROM 'username'@'host';
GRANT SELECT, INSERT, UPDATE, DELETE ON specific_db.* TO 'username'@'host';
🧯 If You Can't Patch
- Implement strict network segmentation and firewall rules to limit MySQL access to essential systems only.
- Apply database user privilege reviews and remove unnecessary permissions, especially CREATE and DROP privileges.
🔍 How to Verify
Check if Vulnerable:
Check MySQL version: SELECT VERSION(); and compare against affected ranges.Check Version:
mysql -u root -p -e 'SELECT VERSION();'Verify Fix Applied:
Verify version is updated beyond affected ranges and check Oracle patch documentation for specific fix verification.📡 Detection & Monitoring
Log Indicators:
- Unexpected MySQL crashes or restarts
- Error logs showing InnoDB corruption or assertion failures
- Multiple failed connection attempts followed by service disruption
Network Indicators:
- Unusual traffic patterns to MySQL port 3306 from unexpected sources
- Multiple rapid queries from single source followed by service unavailability
SIEM Query:
source="mysql_error.log" AND ("crash" OR "assertion" OR "InnoDB" AND "fatal")