CVE-2026-123308 in IntelliJ IDEA
Summary
by MITRE • 11/06/2026
In JetBrains IntelliJ IDEA before 2026.3 code execution via the document import was possible in untrusted projects
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Analysis
by VulDB Data Team • 11/06/2026
The vulnerability identified within JetBrains IntelliJ IDEA prior to version 2026.3 represents a critical security flaw rooted in insufficient validation of input data during the project initialization and file import processes. This issue specifically affects how the integrated development environment handles documents imported from external or untrusted sources, allowing for arbitrary code execution under specific conditions. The core technical deficiency lies in the application's failure to adequately sanitize or restrict operations performed on files that are not part of a trusted, locally verified workspace. When an attacker provides a maliciously crafted project structure or document set, the IDE processes these inputs with elevated privileges relative to standard user interactions, inadvertently executing embedded scripts or configurations as if they were legitimate development artifacts.
From a technical perspective, this vulnerability aligns closely with CWE-94 Improper Control of Generation of Code (Code Injection). The flaw exploits the trust relationship that developers inherently place in their IDE tools, assuming that the software will not execute arbitrary commands without explicit user intent or rigorous security checks. By leveraging features designed for productivity, such as automatic project configuration and dependency resolution, an attacker can inject malicious payloads into the build process or runtime environment of the imported project. This mechanism bypasses standard sandboxing measures because the IDE treats the incoming data as a valid development context rather than untrusted external input. The absence of strict isolation between user-provided configurations and system-level execution contexts enables this escalation of privilege, allowing remote code execution without direct interaction from the victim beyond opening or importing the malicious project file.
The operational impact of this vulnerability is severe, particularly for professionals who frequently collaborate on open-source projects, review third-party libraries, or work with shared repositories where source integrity cannot be guaranteed. An attacker could distribute a seemingly benign archive containing a specially constructed IntelliJ IDEA project file that triggers code execution upon import. This capability facilitates initial access and potential lateral movement within an organization's development infrastructure if the compromised IDE is connected to internal build servers, deployment pipelines, or sensitive version control systems. The ability to execute arbitrary commands means that attackers could exfiltrate source code, inject backdoors into software builds, or use the developer workstation as a pivot point for further network intrusions. Given the central role of IntelliJ IDEA in modern software development workflows, this vulnerability poses a significant risk to intellectual property and system integrity across numerous enterprises relying on JetBrains tools.
Mitigation strategies must focus on immediate patching and enhanced operational security practices. Users are strongly advised to upgrade to version 2026.3 or later, where the vendor has implemented stricter input validation and sandboxing mechanisms for imported documents and project structures. In environments where upgrading is not immediately feasible, developers should exercise extreme caution when opening projects from untrusted sources, utilizing virtual machines or isolated containers to inspect suspicious files before loading them into a primary development environment. Additionally, enabling strict security policies within the IDE that limit automatic script execution during project import can reduce the attack surface. Organizations should also implement application whitelisting and monitor for unusual process creation events originating from IntelliJ IDEA binaries to detect potential exploitation attempts in real time.
This incident underscores the importance of applying secure coding principles even to development tools themselves, as they often operate with high privileges and deep system access. The vulnerability reflects a broader class of risks associated with complex software ecosystems where convenience features may inadvertently compromise security boundaries. By addressing this flaw through timely updates and adopting defense-in-depth strategies such as network segmentation for developer workstations and rigorous code review protocols for external dependencies, organizations can significantly mitigate the risk posed by similar vulnerabilities in future versions or related JetBrains products. Continuous monitoring of vendor advisories and adherence to recommended configuration baselines remain essential components of a robust cybersecurity posture against supply chain attacks targeting development tools.