CVE-2026-109443 in JoySafeter
Summary
by MITRE • 10/20/2026
JoySafeter through 1.0.0 contains a remote code execution vulnerability that allows authenticated users to run operating system commands via an unsandboxed execute tool in Copilot standard mode. Attackers can self-register, select standard mode in the WebSocket chat.start extension, and have the agent invoke subprocess.run with shell=True on the host to access other tenants' data and server secrets.
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Analysis
by VulDB Data Team • 10/20/2026
The vulnerability identified in JoySafeter versions through 1.0.0 represents a critical remote code execution flaw rooted in improper implementation of sandboxing mechanisms within its Copilot standard mode feature. This defect allows authenticated users, who can self-register to gain initial access, to bypass intended security boundaries by leveraging an unsandboxed execute tool. The core technical failure lies in the application's handling of user-supplied input during command execution processes. Specifically, when a user initiates a chat session via the WebSocket chat.start extension and selects standard mode, the backend agent invokes subprocess.run with shell=True enabled on the host system. This configuration effectively delegates control to the operating system's command interpreter rather than executing commands directly through safe application-level functions, thereby creating a direct pathway for arbitrary code execution.
From an operational perspective, this vulnerability poses severe risks to data integrity and confidentiality within multi-tenant environments. Because the executed commands run with the privileges of the host process, attackers can traverse file systems, access sensitive configuration files, and retrieve server secrets that are typically isolated from user-level processes. The ability to execute arbitrary operating system commands means that an attacker is not limited to simple information disclosure; they can potentially install backdoors, modify application logic, or pivot further into internal networks depending on the host's network exposure and privilege level. This undermines the fundamental isolation guarantees expected in SaaS platforms where tenant data must remain strictly segregated from other users' resources.
The technical classification of this flaw aligns closely with CWE-78 Improper Neutralization of Special Elements used in an OS Command, commonly known as OS Command Injection. The use of shell=True without adequate input validation or sanitization is a textbook example of this weakness, as it allows special elements such as semicolons, pipes, and ampersands to alter the intended command structure. Furthermore, from a threat modeling perspective using MITRE ATT&CK frameworks, this vulnerability facilitates techniques associated with Command and Scripting Interpreter abuse (T1059) and potentially System Network Connections Discovery or Data Staged for Exfiltration depending on subsequent attacker actions. The lack of sandboxing in standard mode indicates a failure to implement defense-in-depth strategies that would typically restrict the blast radius of such execution contexts.
Mitigation efforts must prioritize immediate remediation of the command execution mechanism. Developers should replace subprocess.run with shell=True by using direct function calls or ensuring that shell=False is strictly enforced while properly escaping all user inputs if shell invocation remains necessary for specific legacy requirements. Implementing a robust allowlist approach for permitted commands can further restrict potential abuse vectors. Additionally, enforcing strict sandboxing policies for the Copilot standard mode feature is essential to ensure that even if command injection occurs, it cannot impact host-level resources or access other tenants' data. Input validation should be applied at multiple layers, including WebSocket message parsing and application logic handlers, to detect and reject malicious payloads before they reach execution engines. Regular security audits focusing on external control of file descriptors and system processes will help maintain the integrity of these safeguards over time.