CVE-2026-84967 in Extension Plugin
Summary
by MITRE • 09/03/2026
A component of the MongoDB extension for Visual Studio Code does not neutralize special characters in a connection string before that value is placed into a command line the extension composes for an integrated terminal. An unauthenticated remote unauthorized-user who persuades a developer to accept a user-supplied connection target, and then to open the extension's shell feature, can place characters of the unauthorized-user’s choosing into that command line. No privileges on the developer's machine are required, but several user actions are. The confirmation the developer sees does not display the supplied text.
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Analysis
by VulDB Data Team • 09/03/2026
The vulnerability described constitutes a classic case of Command Injection within the MongoDB extension for Visual Studio Code, specifically arising from improper neutralization of special characters in connection strings prior to their inclusion in shell commands. This flaw allows an attacker who can influence the input data used by the application to execute arbitrary operating system commands with the privileges of the user running the IDE. The core technical issue lies in the failure to properly sanitize or escape metacharacters such as semicolons, ampersands, pipes, and backticks within the MongoDB connection string before it is passed to a command-line interpreter. When the extension constructs a shell command for its integrated terminal feature, these unescaped characters are interpreted by the host operating system's command processor rather than being treated as literal data components of the database URI. This misinterpretation enables an attacker to break out of the intended context and inject additional commands that will be executed immediately upon invocation.
From an operational perspective, this vulnerability requires a degree of social engineering or user interaction to exploit effectively. An unauthenticated remote actor cannot directly execute code on the victim's machine but can persuade a developer to accept a maliciously crafted connection target. Once the developer accepts this input and subsequently triggers the extension’s shell feature, which opens an integrated terminal session, the injected payload is executed. The severity of this impact is heightened by the fact that no local privileges are required for exploitation; any standard user account running Visual Studio Code can be compromised if they interact with a malicious connection string. Furthermore, the confirmation dialog presented to the developer does not display the supplied text in its raw form, obscuring the presence of injected commands and making detection through visual inspection nearly impossible without deep technical analysis or logging mechanisms that reveal the underlying command structure.
This vulnerability maps directly to CWE-78 Improper Neutralization of Special Elements used in an OS Command, commonly known as OS Command Injection. The attack vector aligns with ATT&CK technique T1059 Command and Scripting Interpreter, where adversaries use system utilities or scripting languages to execute commands on a target machine. Additionally, the requirement for user interaction places this within the realm of social engineering attacks, potentially categorized under techniques that involve tricking users into performing actions that compromise security. The lack of input validation represents a fundamental flaw in secure coding practices, specifically violating principles related to data integrity and boundary enforcement between application logic and system-level execution environments.
Mitigation strategies must focus on strict input validation and safe command construction practices. Developers should implement allow-list based validation for connection string components, ensuring that only expected alphanumeric characters and standard URI delimiters are permitted. If special characters are necessary, they must be properly escaped or quoted according to the specific shell syntax being used by Visual Studio Code’s integrated terminal backend. Alternatively, the extension could avoid invoking a command-line interpreter altogether by using native API calls for database operations instead of shelling out to external processes like mongo.exe or mongosh. This approach eliminates the attack surface associated with OS-level command execution entirely. Additionally, enhancing user interface transparency is crucial; confirmation dialogs should display sanitized but recognizable representations of input data so users can verify that no unexpected content has been introduced into their environment. Regular security audits and static code analysis tools configured to detect potential injection points in string concatenation operations are also recommended to prevent similar vulnerabilities from being reintroduced during future updates or feature additions.