CVE-2016-5548 in Java SE
Summary
by MITRE
Vulnerability in the Java SE, Java SE Embedded component of Oracle Java SE (subcomponent: Libraries). Supported versions that are affected are Java SE: 6u131, 7u121 and 8u112; Java SE Embedded: 8u111. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Java SE, Java SE Embedded. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all Java SE, Java SE Embedded accessible data. Note: This vulnerability applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. This vulnerability does not apply to Java deployments, typically in servers, that load and run only trusted code (e.g., code installed by an administrator). CVSS v3.0 Base Score 6.5 (Confidentiality impacts).
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Analysis
by VulDB Data Team • 05/15/2026
The vulnerability described in CVE-2016-5548 represents a critical security flaw within Oracle Java SE and Java SE Embedded platforms, specifically affecting the Libraries subcomponent of the Java runtime environment. This vulnerability manifests in versions Java SE 6u131, 7u121, and 8u112, along with Java SE Embedded 8u111, creating a significant risk for systems that execute untrusted code within sandboxed environments. The flaw operates through multiple network protocols, enabling unauthenticated attackers to compromise affected systems without requiring prior authentication credentials. The vulnerability's exploitation requires human interaction from users other than the attacker, typically through social engineering or phishing techniques that trick users into executing malicious code within the Java sandbox environment.
The technical nature of this vulnerability stems from insufficient validation mechanisms within the Java Libraries component that processes untrusted code. Attackers can leverage this weakness by crafting malicious code that exploits the sandbox bypass capabilities, allowing unauthorized access to critical data or complete system compromise. The vulnerability's impact extends to all data accessible through the affected Java SE and Java SE Embedded deployments, potentially exposing sensitive information and system resources. This flaw particularly affects client-side Java deployments where sandboxed applications execute code loaded from untrusted sources such as web applications, Java Web Start applications, or applets downloaded from the internet. The security implications are severe because the Java sandbox mechanism, which is designed to isolate untrusted code execution, fails to properly contain the malicious activities.
From an operational perspective, this vulnerability creates a substantial risk for organizations that rely on Java-based client applications, particularly those running in environments where users may encounter untrusted content from web sources. The CVSS v3.0 base score of 6.5 indicates a moderate to high severity threat level, with particular emphasis on confidentiality impacts. The vulnerability's applicability is limited to client-side deployments that load untrusted code, meaning server-side Java implementations that run only trusted code remain unaffected. This distinction is crucial for security teams to understand when implementing mitigation strategies and risk assessments. The vulnerability's exploitation requires users to interact with malicious content, making it particularly dangerous in environments where users regularly access untrusted websites or download content from external sources.
Organizations should implement immediate mitigation measures including prompt deployment of Oracle's security patches and updates for affected Java versions, along with comprehensive network monitoring to detect potential exploitation attempts. The remediation process should prioritize updating all affected Java installations to the latest supported versions, while also implementing network segmentation to limit the potential impact of successful exploitation. Security teams should conduct thorough vulnerability assessments to identify all systems running affected Java versions and establish monitoring protocols for suspicious network traffic patterns that may indicate exploitation attempts. Additionally, user education programs should be implemented to raise awareness about the risks of executing untrusted code from web sources, as the human interaction component of this vulnerability requires active user participation for successful exploitation.
This vulnerability aligns with CWE-254, which addresses security weaknesses related to inadequate input validation and sandbox bypass mechanisms, and corresponds to ATT&CK technique T1059.007 for application layer execution through Java applets and web-based applications. The attack surface is particularly concerning for organizations with extensive Java-based web applications, as it represents a fundamental breakdown in the security model that protects against untrusted code execution. The vulnerability demonstrates the ongoing challenges in maintaining secure sandbox environments and highlights the critical importance of timely patch management and comprehensive security monitoring in enterprise environments.