CVE-2017-3238 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Optimizer). Supported versions that are affected are 5.5.53 and earlier, 5.6.34 and earlier and 5.7.16 and earlier. 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 v3.0 Base Score 6.5 (Availability impacts).
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Analysis
by VulDB Data Team • 05/15/2026
The vulnerability identified as CVE-2017-3238 resides within the MySQL Server component of Oracle MySQL, specifically within the Server: Optimizer subcomponent. This flaw affects multiple version ranges including 5.5.53 and earlier, 5.6.34 and earlier, and 5.7.16 and earlier versions of the database system. The vulnerability classification as easily exploitable indicates that attackers with minimal privileges and network access can leverage this weakness, making it particularly concerning for database environments where multiple users may have varying levels of access rights. The attack vector operates through multiple protocols, expanding the potential attack surface and reducing the barriers to exploitation.
The technical nature of this vulnerability manifests as a flaw in the query optimizer functionality of MySQL Server, which is responsible for determining the most efficient execution plan for database queries. When maliciously crafted queries are processed through this optimizer, they trigger a condition that leads to server instability. The impact of successful exploitation results in a complete denial of service scenario where the MySQL Server becomes unresponsive or enters a state of frequent crashes. This behavior represents a critical availability impact as defined by the CVSS v3.0 scoring system, with a base score of 6.5 indicating high severity. The vulnerability's potential to cause either a hang or repeatedly crash the server means that legitimate database operations would be severely disrupted, potentially affecting business-critical applications that depend on database availability.
From a cybersecurity perspective, this vulnerability aligns with CWE-122 which describes "Heap Overflow" conditions, though the specific manifestation involves optimizer behavior rather than direct memory corruption. The attack pattern follows typical privilege escalation and denial of service methodologies documented in the MITRE ATT&CK framework under the T1499 category for network denial of service attacks. The low privilege requirement for exploitation makes this particularly dangerous in environments where database users have elevated access rights or where privilege separation is not properly enforced. Organizations implementing MySQL databases in production environments face significant risk from this vulnerability, as it can be exploited by both internal and external threat actors with minimal technical expertise.
Organizations should prioritize immediate patching of affected MySQL versions to mitigate this vulnerability, as the availability impact can severely disrupt business operations. The recommended mitigation strategy includes applying the official Oracle security patches released for this vulnerability, which typically address the specific optimizer behavior that causes the instability. System administrators should also implement network segmentation and access controls to limit the attack surface, ensuring that database servers are not directly accessible from untrusted networks. Additionally, monitoring solutions should be configured to detect unusual patterns in database server behavior that might indicate exploitation attempts, including sudden increases in connection failures or unexpected server restarts. The vulnerability serves as a reminder of the importance of regular security updates and the need for comprehensive vulnerability management programs that can quickly identify and remediate such critical flaws in database systems.