Summary
mcp-ffmpeg contains an OS command injection vulnerability in tools that process video paths and output directories. An attacker who can influence these values may cause shell commands to run with the privileges of the MCP server when the application builds shell command strings unsafely.
mcp-ffmpeg contains an OS command injection vulnerability in tools that process video paths and output directories. An attacker who can influence these values may cause shell commands to run with the privileges of the MCP server when the application builds shell command strings unsafely.
Affected context
The issue affects mcp-ffmpeg deployments through version 1.0.5 when the resize-video, extract-audio, or get-video-info tools receive attacker-influenced videoPath or outputDir values. Risk is present where these values are incorporated into child_process.exec command strings without robust separation from shell syntax.
The issue affects mcp-ffmpeg deployments through version 1.0.5 when the resize-video, extract-audio, or get-video-info tools receive attacker-influenced videoPath or outputDir values. Risk is present where these values are incorporated into child_process.exec command strings without robust separation from shell syntax.
Exploit preconditions
- Attack surface: MCP tools that process video files or output directories
- Required access: Ability to submit or influence tool arguments
- Trigger point: Construction and execution of a shell command by the affected tool
- Why exploitation is possible: User-controlled path values are embedded in a command string interpreted by a shell
- Attack surface: MCP tools that process video files or output directories
- Required access: Ability to submit or influence tool arguments
- Trigger point: Construction and execution of a shell command by the affected tool
- Why exploitation is possible: User-controlled path values are embedded in a command string interpreted by a shell
Why this happens
The underlying flaw is the use of shell-interpreted command construction with insufficient separation between data and executable syntax. When untrusted path values are concatenated into a child_process.exec command, shell metacharacters or quoting boundaries can alter the intended command structure. This behavior maps to CWE-78: Improper Neutralization of Special Elements used in an OS Command, commonly known as OS command injection.
The underlying flaw is the use of shell-interpreted command construction with insufficient separation between data and executable syntax. When untrusted path values are concatenated into a child_process.exec command, shell metacharacters or quoting boundaries can alter the intended command structure. This behavior maps to CWE-78: Improper Neutralization of Special Elements used in an OS Command, commonly known as OS command injection.
Potential impact
- Attackers may execute arbitrary operating-system commands
- The MCP server process may be compromised
- Local files or environment secrets could be accessed
- Data could be modified, deleted, or exfiltrated
- The host or surrounding services could be affected depending on process privileges and network access
- Attackers may execute arbitrary operating-system commands
- The MCP server process may be compromised
- Local files or environment secrets could be accessed
- Data could be modified, deleted, or exfiltrated
- The host or surrounding services could be affected depending on process privileges and network access
General mitigation guidance
Mitigation generally focuses on ensuring that file paths and directories remain data rather than shell syntax.
Common defensive patterns include:
- Prefer direct process-spawning APIs that pass arguments separately instead of invoking a shell
- Apply strict path validation and constrain inputs to approved directories
- Use allowlists for expected filename and directory formats
- Avoid constructing commands through string concatenation or interpolation
- Run the MCP server with the minimum filesystem, operating-system, and network privileges required
- Isolate media-processing workloads and limit access to sensitive environment data
Mitigation generally focuses on ensuring that file paths and directories remain data rather than shell syntax.
Common defensive patterns include:
- Prefer direct process-spawning APIs that pass arguments separately instead of invoking a shell
- Apply strict path validation and constrain inputs to approved directories
- Use allowlists for expected filename and directory formats
- Avoid constructing commands through string concatenation or interpolation
- Run the MCP server with the minimum filesystem, operating-system, and network privileges required
- Isolate media-processing workloads and limit access to sensitive environment data
How teams detect issues like this
Detection approaches include:
- Static analysis rules identifying child_process.exec calls that interpolate request or tool arguments
- Code review checks for shell command construction involving paths, filenames, or directory values
- Runtime monitoring for unexpected child processes, command interpreters, or anomalous media-tool arguments
- Policy enforcement requiring argument-array process APIs for commands that handle external input
- Automated security review tools that flag unsanitized data flows into shell execution functions
Detection approaches include:
- Static analysis rules identifying child_process.exec calls that interpolate request or tool arguments
- Code review checks for shell command construction involving paths, filenames, or directory values
- Runtime monitoring for unexpected child processes, command interpreters, or anomalous media-tool arguments
- Policy enforcement requiring argument-array process APIs for commands that handle external input
- Automated security review tools that flag unsanitized data flows into shell execution functions
