CVE-2020-14830 in MySQL Server
Summary
by MITRE • 10/21/2020
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.21 and prior. Easily exploitable vulnerability allows low privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 6.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
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Analysis
by VulDB Data Team • 08/10/2025
The vulnerability identified as CVE-2020-14830 resides within the MySQL Server optimizer component of Oracle MySQL, affecting versions 8.0.21 and earlier. This represents a significant security weakness that operates at the core of database query processing, where the optimizer is responsible for determining the most efficient execution plan for SQL queries. The flaw manifests in how the MySQL server handles certain query optimization scenarios, creating a pathway for malicious actors to exploit the system's query processing capabilities. The vulnerability's classification as easily exploitable indicates that the attack vector requires minimal technical sophistication and can be executed by attackers with network access through multiple protocols, making it particularly dangerous in production environments where database servers are often exposed to network traffic.
The technical nature of this vulnerability stems from improper handling of specific optimizer operations that can lead to resource exhaustion or invalid memory access patterns during query execution. When an attacker crafts malicious SQL queries that trigger the vulnerable code path within the optimizer, the system can become unresponsive or crash repeatedly, resulting in a complete denial of service condition. This type of vulnerability falls under the CWE-121 category of Buffer Errors, specifically related to improper handling of memory operations during query processing. The attack requires only low privileges and network access, meaning that even users with minimal database permissions could potentially exploit this weakness. The CVSS 3.1 score of 6.5 reflects the availability impact severity, where the primary consequence is the complete disruption of database services through repeated crashes or system hangs.
From an operational perspective, this vulnerability poses a critical threat to database availability and system reliability, particularly in environments where MySQL serves as a core component of enterprise applications. The ability to cause complete denial of service through repeated crashes can result in significant business disruption, especially in mission-critical systems where database uptime is essential. Organizations running affected MySQL versions face the risk of service interruption, data access delays, and potential revenue loss due to system unavailability. The vulnerability's impact extends beyond simple service disruption as it can affect database integrity and performance monitoring capabilities, making it difficult for administrators to detect and respond to attacks effectively.
Mitigation strategies for CVE-2020-14830 should prioritize immediate patching of affected MySQL versions to the latest releases that contain the necessary security fixes. Organizations should implement network segmentation and access controls to limit exposure of MySQL servers to unnecessary network traffic, reducing the attack surface for potential exploitation. Database administrators should also consider implementing query monitoring and rate limiting mechanisms to detect and prevent malicious query patterns that might trigger the vulnerability. Additionally, regular security assessments and vulnerability scanning should be conducted to identify other potential weaknesses in the database infrastructure. The ATT&CK framework categorizes this vulnerability under the T1499 technique for Network Denial of Service, highlighting the importance of implementing proper network security controls to prevent unauthorized access to database systems. Organizations should also maintain comprehensive incident response procedures specifically designed to address database service disruptions, ensuring rapid recovery and minimal business impact when such vulnerabilities are exploited.