CVE-2026-100256 in IntelliJ IDEA
Summary
by MITRE • 09/30/2026
In JetBrains IntelliJ IDEA before 2026.2.3 rCE via Structural Search script constraints was possible in untrusted projects
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Analysis
by VulDB Data Team • 09/30/2026
The vulnerability identified involves a critical remote code execution flaw within the structural search and replace functionality of JetBrains IntelliJ IDEA prior to version 2026.2.3. This security issue stems from insufficient validation and sanitization mechanisms applied to user-supplied input when processing Structural Search templates in untrusted project contexts. The architectural design of IntelliJ IDEA allows developers to define complex patterns for code analysis using a specialized scripting language that supports regular expressions, variable substitution, and conditional logic. While this feature is essential for advanced refactoring and static analysis workflows, it introduces an attack surface if the integrity of the input data cannot be guaranteed. In untrusted projects, which may include dependencies from external repositories or shared workspace files, malicious actors can craft specific structural search configurations that exploit parsing ambiguities or execution engine weaknesses to achieve arbitrary code execution on the host machine running the IDE.
From a technical perspective, the flaw likely resides in how the IDE processes constraints and templates defined within these scripts. Structural Search allows for the definition of patterns that match source code elements based on their structure rather than just text content. When an untrusted project is opened or analyzed, the IDE may automatically apply certain search configurations or allow users to execute custom searches without adequate sandboxing. If the parsing logic fails to properly escape special characters or restricts the execution context appropriately, a crafted payload can bypass intended security boundaries. This could involve injecting malicious commands into template variables that are subsequently evaluated by an internal scripting engine or interpreter embedded within the IDE's core components. The lack of strict isolation between the code analysis module and the system shell or runtime environment facilitates this escalation of privileges, allowing external input to dictate program flow beyond its intended scope.
The operational impact of this vulnerability is severe, as it enables remote code execution without requiring user interaction beyond opening a malicious project file or executing a specific search command within an untrusted workspace. An attacker who can distribute a specially crafted IntelliJ IDEA project structure could compromise the development environment of any developer who opens and analyzes it. This compromises not only the confidentiality and integrity of the local system but also poses significant risks to supply chain security, as compromised build environments may lead to the injection of malicious code into downstream software artifacts. The ability to execute arbitrary commands means that attackers can exfiltrate sensitive source code, install persistent backdoors, or use the developer's machine as a pivot point for further network intrusions. Given the widespread adoption of IntelliJ IDEA among enterprise development teams, this vulnerability represents a high-impact threat vector targeting critical infrastructure and intellectual property assets.
Mitigation strategies primarily involve immediate upgrading to JetBrains IntelliJ IDEA version 2026.2.3 or later, where these constraints have been rigorously validated and patched by the vendor. Until an upgrade is feasible, organizations should enforce strict policies regarding untrusted projects, discouraging developers from opening source code repositories that are not verified for integrity. Utilizing IDE settings to disable automatic structural search execution on project open can also reduce exposure. Furthermore, implementing network segmentation and endpoint detection and response solutions can help identify anomalous process executions originating from the IDE binary. From a broader security architecture standpoint, this incident highlights the necessity of applying zero-trust principles even within trusted development tools, ensuring that code analysis features operate in isolated sandboxes with minimal privileges to prevent exploitation through complex input vectors like structural search scripts.
This vulnerability aligns with CWE-94 Improper Control of Generation of Code (Code Injection) and CWE-78 Improper Neutralization of Special Elements used in an OS Command (OS Command Injection), depending on the specific mechanism exploited within the scripting engine. In terms of adversary tactics, it maps to MITRE ATT&CK technique T1059 Command and Scripting Interpreter, where attackers leverage built-in system tools or application features to execute malicious commands. The exploitation path also reflects aspects of T1204 User Execution, as initial access often requires the victim to open a malicious file or project configuration within the IDE. Addressing this issue requires both immediate patch management and long-term architectural reviews of how third-party code is processed by development tools to ensure that powerful features like structural search do not become vectors for system compromise.