CVE-2021-35607 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 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 • 05/17/2025
The vulnerability identified as CVE-2021-35607 represents a critical availability issue within Oracle MySQL Server affecting versions 8.0.26 and earlier. This weakness resides in the Server: DML component, which governs data manipulation language operations that form the core of database interaction. The flaw manifests as a denial of service condition that can be triggered by attackers with minimal privileges and network access through multiple protocols, making it particularly dangerous in production environments where database availability is paramount. The vulnerability's classification as easily exploitable means that threat actors require little specialized knowledge or resources to successfully compromise affected systems.
The technical nature of this vulnerability stems from improper handling of certain DML operations within the MySQL server architecture, specifically related to how the system processes and manages data manipulation commands. When exploited, the vulnerability allows an attacker to cause the MySQL server to either hang indefinitely or crash repeatedly, effectively rendering the database service unavailable to legitimate users and applications. This behavior aligns with the CVSS 3.1 scoring system which assigns a base score of 6.5, reflecting the high availability impact and the relatively low attack complexity required to exploit the flaw. The vulnerability's vector indicates network-based access with low attack complexity, requiring only low privileges and no user interaction, making it particularly concerning for database administrators managing enterprise systems.
The operational impact of CVE-2021-35607 extends beyond simple service disruption to potentially cause significant business interruptions and data access problems. Organizations relying on MySQL databases for critical applications face the risk of complete service outages that can cascade through dependent systems and applications. The vulnerability's ability to cause frequent repeatable crashes means that even brief exploitation attempts can result in sustained service degradation, complicating recovery efforts and potentially leading to extended downtime. This type of vulnerability directly impacts the availability aspect of the CIA triad and can be classified under CWE-400 as an Uncontrolled Resource Consumption vulnerability, where the MySQL server's resources are exhausted through improper handling of DML operations. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under the T1499 category for Network Denial of Service, specifically targeting database services to cause availability disruption.
Organizations should implement immediate mitigations including applying the latest Oracle security patches and updates to address the vulnerability in affected MySQL versions. System administrators should also consider implementing network segmentation and access controls to limit exposure to only trusted networks and users. Monitoring solutions should be configured to detect unusual patterns of database connection attempts or service disruptions that might indicate exploitation attempts. The vulnerability's characteristics suggest that defensive measures should focus on network-level controls and application-level monitoring rather than relying solely on traditional database security measures. Additionally, implementing proper database access controls and privilege management can help reduce the attack surface, as the vulnerability requires only low-privileged network access to exploit. Regular security assessments and vulnerability scanning should be conducted to identify systems running affected MySQL versions and ensure timely patch deployment across all database environments.