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How CVE-2025-21540 Works
This vulnerability exists in MySQL Server’s privilege management component, affecting versions 8.0.40 and prior, 8.4.3 and prior, and 9.1.0 and prior. A low-privileged attacker with network access can exploit improper privilege validation during SQL operations. When specific queries are executed, MySQL fails to properly enforce role-based access controls, allowing unauthorized data modification (INSERT/UPDATE/DELETE) and partial data read access. The flaw stems from incorrect privilege checks when handling temporary tables or certain JOIN operations, enabling attackers to bypass intended restrictions.
DailyCVE Form
Platform: MySQL
Version: <=9.1.0
Vulnerability: Privilege Escalation
Severity: Medium
Date: 04/08/2025
What Undercode Say:
Exploitation:
-- Example exploit leveraging improper privilege checks CREATE TEMPORARY TABLE temp_exploit ENGINE=InnoDB SELECT FROM restricted_db.users; GRANT SELECT ON temp_exploit TO 'lowpriv_user'@'%';
Detection:
Check MySQL version mysql --version | grep -E "8.0.[0-40]|8.4.[0-3]|9.1.0"
Mitigation:
- Apply Oracle patches for MySQL 8.0.41+, 8.4.4+, or 9.1.1+.
2. Restrict network access via MySQL config:
[bash] bind-address = 127.0.0.1 skip-networking
Audit Commands:
-- List users with potential overprivileged access SELECT user, host FROM mysql.user WHERE Insert_priv='Y' OR Update_priv='Y';
Workaround:
Revoke unnecessary privileges:
REVOKE ALL PRIVILEGES ON . FROM 'lowpriv_user'@'%'; FLUSH PRIVILEGES;
Log Analysis:
grep -E "CREATE TEMPORARY|GRANT" /var/log/mysql/mysql.log
CVSS 4.0 Metrics:
- Attack Vector: Network
- Privileges Required: Low
- User Interaction: None
- Confidentiality Impact: Low
- Integrity Impact: Low
References:
Reported By: https://nvd.nist.gov/vuln/detail/CVE-2025-21540
Extra Source Hub:
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