CVE-2025-21497
📋 TL;DR
This vulnerability in MySQL Server's InnoDB component allows authenticated high-privileged attackers to cause denial of service (server crashes/hangs) or modify some data. Affected versions include MySQL 8.0.40 and prior, 8.4.3 and prior, and 9.1.0 and prior.
💻 Affected Systems
- Oracle MySQL Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete MySQL Server outage (DoS) combined with unauthorized data modification, potentially affecting critical database operations and data integrity.
Likely Case
Service disruption through server crashes or hangs, requiring restart and causing application downtime.
If Mitigated
Limited impact due to restricted high-privilege access requirements and network segmentation.
🎯 Exploit Status
CVSS indicates 'easily exploitable' but requires high-privilege credentials. No public exploit code identified in references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 8.0.40, 8.4.3, and 9.1.0 (check Oracle Critical Patch Update for exact fixed versions)
Vendor Advisory: https://www.oracle.com/security-alerts/cpujan2025.html
Restart Required: Yes
Instructions:
1. Review Oracle Critical Patch Update Advisory for exact fixed versions. 2. Apply MySQL patches from Oracle. 3. Restart MySQL service. 4. Verify patch application.
🔧 Temporary Workarounds
Restrict High-Privilege Access
allLimit accounts with administrative privileges to reduce attack surface
REVOKE SUPER, PROCESS, FILE, SHUTDOWN, RELOAD FROM 'user'@'host';
REVOKE ALL PRIVILEGES ON *.* FROM 'user'@'host';
Network Segmentation
linuxRestrict network access to MySQL ports (3306 default) to trusted sources only
iptables -A INPUT -p tcp --dport 3306 -s trusted_ip -j ACCEPT
iptables -A INPUT -p tcp --dport 3306 -j DROP
🧯 If You Can't Patch
- Implement strict access controls for high-privilege MySQL accounts
- Monitor for unusual database crashes or connection attempts from admin accounts
🔍 How to Verify
Check if Vulnerable:
Check MySQL version: SELECT VERSION(); and compare against affected ranges (8.0.40 and prior, 8.4.3 and prior, 9.1.0 and prior)Check Version:
mysql -u root -p -e 'SELECT VERSION();'Verify Fix Applied:
Verify version is above affected ranges and check Oracle advisory for specific fixed versions📡 Detection & Monitoring
Log Indicators:
- Unexpected MySQL crashes/restarts in error logs
- Multiple failed connection attempts from admin accounts
- InnoDB corruption or crash messages
Network Indicators:
- Unusual traffic patterns to MySQL port from unexpected sources
- Multiple protocol connections to MySQL from single source
SIEM Query:
source="mysql_error.log" ("crash" OR "shutdown" OR "InnoDB") AND severity=ERROR