CVE-2016-8327 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Replication). Supported versions that are affected are 5.6.34 and earlier and 5.7.16 and earlier. Difficult to exploit 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 v3.0 Base Score 4.4 (Availability impacts).
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Analysis
by VulDB Data Team • 05/15/2026
The vulnerability identified as CVE-2016-8327 resides within the MySQL Server replication functionality, specifically affecting Oracle MySQL versions 5.6.34 and earlier, as well as 5.7.16 and earlier. This flaw operates within the server replication subsystem, which is critical for maintaining data consistency across multiple MySQL instances in distributed database environments. The vulnerability's classification as a high-privilege attack vector indicates that it requires an attacker with elevated privileges to exploit effectively, though the attack surface extends across multiple network protocols. The availability impact is significant as successful exploitation can lead to complete denial of service conditions that cause the MySQL server to hang or repeatedly crash, rendering database services inaccessible to legitimate users.
The technical nature of this vulnerability stems from improper handling of replication events within the MySQL server architecture, creating conditions where maliciously crafted replication data can trigger memory corruption or resource exhaustion scenarios. This flaw operates at the intersection of database replication protocols and server process management, where the server fails to properly validate or handle certain replication commands that could originate from network connections. The difficulty of exploitation suggests that while the vulnerability exists, it requires specific conditions and potentially sophisticated attack techniques to successfully compromise the target system. The CVSS v3.0 base score of 4.4 reflects the moderate severity of the availability impact, though the potential for complete system downtime makes this a serious concern for database administrators and security professionals.
From an operational perspective, this vulnerability presents significant risks to database availability and service continuity, particularly in environments where MySQL replication is heavily utilized for high-availability setups, master-slave configurations, or distributed database architectures. Organizations relying on MySQL replication for business-critical applications face potential downtime scenarios that could result in substantial financial losses and service disruption. The vulnerability's impact extends beyond simple service interruption as it can create cascading failures in replicated environments where multiple database instances depend on each other for data consistency. The complete denial of service condition affects not just the primary database server but potentially the entire replication cluster, making this vulnerability particularly dangerous in enterprise environments where database uptime is critical for business operations.
The attack surface for this vulnerability encompasses multiple network protocols including TCP/IP connections that MySQL replication typically uses for communication between master and slave servers. This makes the vulnerability accessible through various attack vectors including direct network connections, potentially through compromised internal network access or even external network exposure if replication ports are not properly secured. The high-privilege requirement for exploitation suggests that attackers would need either legitimate administrative credentials or have already achieved a foothold in the network environment to effectively leverage this vulnerability. Security practitioners should consider this vulnerability in the context of broader network security controls and privilege management policies, as the requirement for elevated access does not eliminate the potential for significant impact.
Mitigation strategies should focus on immediate patching of affected MySQL versions to the latest available releases, which would address the underlying replication handling issues that create the vulnerability conditions. Organizations should implement network segmentation to limit access to MySQL replication ports and protocols, ensuring that only authorized systems can communicate with replication endpoints. Monitoring and logging of replication activities should be enhanced to detect anomalous replication behavior that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and may also relate to CWE-122 for heap-based buffer overflow conditions that can occur during replication data processing. From an ATT&CK framework perspective, this vulnerability could be leveraged during the privilege escalation and persistence phases of an attack, particularly when attackers seek to disrupt database services and maintain access to compromised systems. Regular vulnerability assessments and security testing should be conducted to identify similar replication-related vulnerabilities that could pose similar availability risks to database infrastructure.