CVE-2017-3256 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Replication). Supported versions that are affected are 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-2017-3256 represents a critical availability threat within Oracle MySQL Server's replication functionality. This weakness exists in the server component specifically within the replication subsystem, affecting MySQL versions 5.7.16 and earlier. The vulnerability's classification as easily exploitable indicates that attackers with minimal privileges and network access can leverage this flaw to compromise the targeted database server. The attack vector operates through multiple network protocols, making the vulnerability particularly dangerous as it can be exploited across different communication channels.
The technical flaw manifests as a condition that allows unauthorized manipulation of the replication process, leading to a denial of service scenario where the MySQL Server becomes unresponsive or enters a continuous crash cycle. This type of vulnerability directly impacts the availability aspect of the CIA triad, as defined by the Common Weakness Enumeration framework under CWE-400. The vulnerability's design flaw likely stems from inadequate input validation or improper error handling within the replication protocol implementation, creating a path for malicious actors to trigger resource exhaustion or state corruption.
From an operational perspective, the impact of this vulnerability extends beyond simple service disruption to potentially severe business consequences. A successful exploitation can result in complete system unavailability, affecting all database operations and potentially causing cascading failures throughout dependent applications and services. The CVSS v3.0 base score of 6.5 indicates a medium to high severity threat that requires immediate attention from system administrators and security teams. The vulnerability's ability to cause repeated crashes means that even a single exploitation attempt can lead to prolonged service outages.
The threat landscape for this vulnerability aligns with ATT&CK framework techniques related to privilege escalation and denial of service operations. Attackers can leverage this weakness to systematically degrade service availability without requiring elevated privileges, making it particularly attractive for malicious actors seeking to disrupt business operations. The replication subsystem's role in database synchronization and data consistency makes this vulnerability especially dangerous as it can affect data integrity across multiple server instances. Organizations should implement immediate patch management strategies and network segmentation to limit the attack surface, while monitoring for suspicious replication traffic patterns that may indicate exploitation attempts.
Mitigation strategies should focus on applying the official Oracle patches released for this vulnerability, which address the underlying replication protocol handling issues. Network-level protections including firewall rules to restrict replication traffic and intrusion detection systems to monitor for anomalous replication behavior should be implemented. Additionally, organizations should consider disabling unnecessary replication features and implementing robust monitoring solutions to detect early signs of exploitation attempts. The vulnerability's impact on availability makes it crucial for organizations to maintain redundant database systems and implement proper backup and recovery procedures to ensure business continuity during potential exploitation events.