Description

In JetBrains Junie CLI before 26.8.24 command execution was possible via the Allow Similar Commands option

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.0",
  "pubDate": "2026-11-06T11:17:10.857Z",
  "pubdate": "2026-11-06T11:17:10.857Z",
  "executiveSummary": "A command execution vulnerability has been identified in the JetBrains Junie CLI versions prior to 26.8.24.\nThe vulnerability stems from improper handling of user-controllable input within the 'Allow Similar Commands' feature.\nSuccessful exploitation allows an unauthenticated attacker to execute arbitrary commands on the underlying host operating system with the privileges of the CLI process.\nThis vulnerability poses a critical risk to the integrity, confidentiality, and availability of the affected system, as it permits unauthorized code execution.\nThe flaw occurs due to the improper sanitization or validation of input passed through the vulnerable configuration option, which is subsequently interpreted or executed by the system shell or underlying command interpreter.\nAttackers can leverage this mechanism to bypass intended application constraints and execute malicious payloads, potentially leading to a full system compromise.\nExploitation does not inherently require high-level privileges beyond the ability to influence the input processed by the CLI tool.",
  "technicalDetails": "The vulnerability resides within the logic associated with the 'Allow Similar Commands' feature in JetBrains Junie CLI. This feature is intended to provide enhanced usability by suggesting or automatically executing commands that closely match user input. However, the mechanism fails to correctly sanitize or escape arguments before they are passed to the system's command execution environment.\nThe root cause is a failure to implement proper command parameterization or strict input validation when processing data handled by the 'Allow Similar Commands' logic. When this option is enabled, the CLI facilitates the execution of commands based on input that has not been adequately isolated from the command execution context.\nAn attacker can exploit this flaw by providing crafted input that triggers the 'Allow Similar Commands' functionality. By injecting shell metacharacters (such as ';', '&', '|', or backticks) into the input field or configuration, an attacker can break out of the intended command context and append arbitrary malicious commands. When the CLI subsequently processes this crafted input, the underlying system interpreter executes both the legitimate command and the attacker-injected payload.\nThe attack flow follows these steps: 1. The attacker identifies the use of the 'Allow Similar Commands' feature within the JetBrains Junie CLI environment. 2. The attacker crafts a malicious input string designed to terminate the intended command and initiate a secondary command execution. 3. The attacker submits the crafted string through the interface or configuration file used by the CLI. 4. The CLI, failing to sanitize the input, passes the entire string to the system shell. 5. The shell interprets the malicious payload as a separate instruction, leading to command execution.\nThe vulnerable component is the processing logic for the 'Allow Similar Commands' functionality. Affected versions include all iterations of JetBrains Junie CLI prior to 26.8.24. Authentication and privilege requirements depend on the deployment context of the CLI; however, if the CLI is used in an automated or CI/CD environment, the vulnerability can be exploited by any user or process capable of supplying input to the CLI execution environment.\nPost-exploitation impact includes unauthorized access to system resources, the potential for data exfiltration, lateral movement within the network, and the deployment of further malicious software or persistence mechanisms, depending on the privileges of the user running the JetBrains Junie CLI process."
}