CVE-2026-75414 in AntFlow
Summary
by MITRE • 08/27/2026
In AntFlow V2.0.0, ActivitiTest.java enables users to execute JUEL expressions without filtering the user input, which leads to a command execution vulnerability.
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified in AntFlow version 2.0.0 represents a critical server-side code injection flaw rooted in improper handling of dynamic expression evaluation within the Activiti workflow engine integration. Specifically, the file ActivitiTest.java contains logic that processes user-supplied input directly into Java Unified Expression Language (JUEL) evaluators without implementing adequate sanitization or validation mechanisms. JEL is commonly used for evaluating expressions in web applications to bind data to UI components, but when exposed to untrusted input, it becomes a potent vector for remote code execution because the underlying engine can invoke arbitrary methods and constructors within the Java Virtual Machine environment.
This technical flaw allows an authenticated attacker who has access to the specific workflow endpoints or forms managed by AntFlow to inject malicious JUEL expressions into fields that are processed by this vulnerable component. By crafting input strings that contain valid EL syntax combined with dangerous method invocations, such as accessing java.lang.Runtime or javax.script.ScriptEngineManager classes, the attacker can force the application server to execute system commands on behalf of the user running the web service process. This bypasses standard security controls because the execution occurs within the context of the application itself rather than through external network services that might be protected by firewalls or intrusion detection systems.
The operational impact of this vulnerability is severe, as it effectively grants an attacker full control over the underlying operating system hosting the AntFlow instance. Once command execution is achieved, the threat actor can escalate privileges to access sensitive data stored within the workflow database, modify configuration files, install backdoors for persistent access, or pivot into other internal network segments depending on the isolation level of the server environment. This compromises not only the confidentiality and integrity of the application but also potentially destabilizes the broader infrastructure if critical services are impacted by malicious commands such as resource exhaustion attacks or data destruction routines.
From a classification perspective, this vulnerability aligns with CWE-94 Improper Control of Generation of Code (Code Injection) under the category of Server-Side Request Forgery and injection flaws where user input is directly evaluated as code. In terms of adversary behavior mapping to MITRE ATT&CK techniques, this scenario corresponds to T1059 Command and Scripting Interpreter, specifically leveraging JUEL or Java-based scripting engines for execution, which falls under the broader tactic of Execution within the Enterprise Attack framework. The lack of input validation also reflects CWE-20 Improper Input Validation, indicating a fundamental failure in the secure coding practices during the development phase of the ActivitiTest module.
Mitigation strategies must prioritize immediate remediation through software updates provided by the vendor if available for AntFlow version 2.0.0 or later versions where this issue has been patched. In cases where patching is not immediately feasible, administrators should implement strict input validation and allowlisting at the application layer to ensure that only expected character sets are processed by expression evaluators. Additionally, deploying Web Application Firewalls with rules capable of detecting JUEL syntax patterns can provide a temporary defensive barrier against exploitation attempts while permanent fixes are applied. It is also recommended to enforce least-privilege principles for the user account running the AntFlow service, ensuring that even if code execution occurs, the attacker cannot perform high-level administrative actions on the host system.