CVE-2026-94109 in openEQUELLA
Summary
by MITRE • 09/20/2026
openEQUELLA versions before 2026.1.0 contain a remote code execution vulnerability in FreeMarker template compilation due to an unsandboxed TemplateClassResolver configuration. Authenticated attackers can inject malicious template expressions through collection summaries, dashboard portlets, or MIME templates to instantiate dangerous classes like freemarker.template.utility.Execute and invoke Runtime.exec for arbitrary command execution.
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Analysis
by VulDB Data Team • 09/20/2026
The vulnerability identified in openEQUELLA versions prior to 2026.1.0 represents a critical remote code execution flaw rooted in the improper configuration of the FreeMarker template engine's security sandboxing mechanisms. Specifically, the issue arises from an unsandboxed TemplateClassResolver that permits unrestricted access to Java classes during the template compilation and rendering process. This architectural weakness allows authenticated users to bypass intended isolation boundaries within the application server environment. By leveraging this misconfiguration, attackers can inject malicious expressions into FreeMarker templates, effectively turning a content management feature into a vector for arbitrary command execution on the underlying host system.
The technical mechanism of exploitation involves the injection of dangerous class instantiations through specific user-controlled input vectors such as collection summaries, dashboard portlets, or MIME templates. The core danger lies in the ability to instantiate classes from the freemarker.template.utility package, particularly Execute and Exec. These utility classes are designed for advanced template functionality but pose severe security risks when accessible without restriction. An attacker can craft a template expression that calls Runtime.exec with arbitrary operating system commands. Because openEQUELLA is typically deployed in enterprise environments handling sensitive educational or institutional data, the ability to execute shell commands as the application user grants complete control over the server infrastructure, potentially leading to full system compromise, data exfiltration, and lateral movement within the network.
From a classification perspective, this vulnerability aligns with CWE-94 Improper Control of Generation of Code (Code Injection) and CWE-78 OS Command Injection. The root cause is categorized under CWE-201 Insertion of Sensitive Information into Sent Data or more accurately CWE-693 Protection Mechanism Failure due to the lack of effective sandboxing in the template engine configuration. In terms of adversary tactics, this exploit maps directly to MITRE ATT&CK technique T1059 Command and Scripting Interpreter, specifically sub-techniques involving shell execution like T1059.004 Unix Shell or T1059.007 Windows Command Shell depending on the operating system. The attack vector is classified as Remote (Network) with Authentication Required, indicating that while it does not require network-level access without credentials, the presence of valid user accounts significantly expands the threat surface for potential exploitation by insider threats or compromised legitimate users.
The operational impact of this vulnerability extends beyond immediate code execution to include severe risks to data integrity and confidentiality. An attacker gaining command-line access can modify database contents, alter application configurations, install backdoors, or use the server as a pivot point for further attacks against internal networks. Given that openEQUELLA often stores intellectual property, student records, and proprietary research materials, such an intrusion could result in significant regulatory compliance violations under frameworks like GDPR, FERPA, or HIPAA depending on the institution's data handling practices. The persistence of this vulnerability across multiple versions highlights a systemic issue in default security configurations that must be addressed at both the application level and through rigorous deployment hardening procedures.
Mitigation strategies should prioritize immediate upgrading to openEQUELLA version 2026.1.0 or later, where the TemplateClassResolver is properly sandboxed by default to prevent access to dangerous utility classes. For environments unable to upgrade immediately due to compatibility constraints, administrators must implement strict input validation and output encoding for all user-supplied data rendered through FreeMarker templates. Additionally, deploying a Web Application Firewall with rules specifically targeting template injection patterns can provide an additional layer of defense. It is also critical to enforce the principle of least privilege by running the openEQUELLA application under a dedicated service account with minimal operating system permissions, thereby limiting the potential damage if exploitation occurs. Regular security audits and static code analysis focused on template engine configurations are recommended to detect similar misconfigurations in other integrated components.