CVE-2021-2479 in MySQL Server
Summary
by MITRE • 10/20/2021
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: DML). Supported versions that are affected are 8.0.26 and prior. Easily exploitable vulnerability allows high 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 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
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Analysis
by VulDB Data Team • 05/17/2025
The vulnerability identified as CVE-2021-2479 represents a critical availability threat within Oracle MySQL Server version 8.0.26 and earlier releases. This weakness resides within the Server: DML component, which governs data manipulation language operations that form the backbone of database interactions. The vulnerability's classification as easily exploitable indicates that attackers with high privileges and network access can leverage this flaw to disrupt database services. The CVSS 3.1 scoring system assigns a base score of 4.9, reflecting moderate severity with significant availability impacts that can lead to complete denial of service conditions. The attack vector requires network access via multiple protocols, suggesting that the vulnerability can be exploited across various communication channels that MySQL supports.
The technical flaw manifests as a condition that allows authenticated attackers with elevated privileges to trigger system instability resulting in database server crashes or indefinite hangs. This type of vulnerability falls under the CWE-119 category of "Improper Access to Memory" or similar memory corruption issues that can occur during data manipulation operations. When exploited, the vulnerability enables attackers to cause repeated crashes that can render the MySQL server completely unavailable to legitimate users. The impact extends beyond simple disruption as the repeated nature of the crashes can prevent database recovery operations and potentially cause data integrity issues. The vulnerability's designation as affecting high privileged attackers indicates that it requires authentication, likely through legitimate database access credentials, but does not necessitate administrative privileges.
From an operational perspective, this vulnerability poses substantial risk to database-dependent applications and services that rely on continuous MySQL server availability. The potential for complete denial of service can severely impact business operations, particularly in environments where database availability is critical for transaction processing, reporting, or other essential functions. Organizations running MySQL Server versions prior to 8.0.26 face significant exposure to this vulnerability, as the flaw affects the core data manipulation capabilities that form the foundation of database operations. The vulnerability can be particularly damaging in production environments where database uptime is essential for maintaining business continuity and service level agreements.
Mitigation strategies for CVE-2021-2479 should prioritize immediate patching of affected MySQL Server installations to version 8.0.27 or later, which contains the necessary fixes for this vulnerability. Organizations should implement network segmentation and access controls to limit exposure to only authorized users with legitimate database access requirements. The principle of least privilege should be enforced to ensure that database users have only the minimum necessary permissions required for their operations. Additionally, monitoring and logging configurations should be enhanced to detect unusual patterns of database access or system behavior that might indicate exploitation attempts. Network-based intrusion detection systems can help identify potential exploitation attempts by monitoring for abnormal traffic patterns or access patterns that could indicate malicious activity targeting this specific vulnerability. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for "Endpoint Denial of Service" as it specifically targets availability through system instability and crash conditions.