CVE-2020-37279 in easy-pdf-merge
Summary
by MITRE • 10/13/2026
easy-pdf-merge 0.1.0 through 0.2.6 contains an OS command injection vulnerability that allows attackers to execute commands by injecting shell metacharacters into source paths, destination path, or maxHeap option. Attackers can supply file names or options containing double quotes, semicolons, $() or backticks, which child_process.exec() runs through a shell with the Node.js process privileges.
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Analysis
by VulDB Data Team • 10/13/2026
The vulnerability identified in easy-pdf-merge versions 0.1.0 through 0.2.6 represents a critical OS command injection flaw rooted in improper neutralization of special elements used in an operating system command, commonly classified under CWE-78. This security defect arises from the application's reliance on Node.js child_process.exec() to handle file operations and configuration parameters without adequate sanitization or validation of user-supplied input. The core technical failure lies in the direct concatenation of unsanitized strings into shell commands, allowing attackers to inject arbitrary shell metacharacters such as double quotes, semicolons, command substitution symbols like $(), and backticks. When these inputs are processed by child_process.exec(), they are interpreted not merely as data but as executable code within the context of the underlying operating system shell, thereby bypassing intended application logic boundaries.
From an operational perspective, this vulnerability enables remote attackers to achieve arbitrary code execution on the host system running the vulnerable software. By crafting malicious file names or manipulating command-line options such as maxHeap, an attacker can inject commands that are executed with the same privileges as the Node.js process itself. This means if the application is run with elevated permissions, the resulting compromise could grant full control over the server environment, including access to sensitive files, installation of malware, pivoting to other network assets, or exfiltration of data. The impact extends beyond simple denial of service, as it fundamentally breaks the isolation between user input and system-level operations, turning a PDF merging utility into a potential vector for complete system takeover.
In terms of threat modeling and industry standards, this vulnerability aligns with MITRE ATT&CK technique T1059, specifically Command and Scripting Interpreter, where attackers use native tools to execute commands on compromised systems. The attack path typically involves supplying malicious input through the application interface or command line arguments, which are then passed directly to the shell interpreter. This behavior is a classic example of insecure dynamic code execution, where user-controlled data influences the structure of an executed command without proper validation against a whitelist of allowed characters or patterns.
To mitigate this risk, developers must immediately upgrade to patched versions of easy-pdf-merge that address these injection vectors by implementing strict input validation and avoiding shell interpretation for file operations. Best practices dictate replacing child_process.exec() with safer alternatives such as child_process.spawn(), which does not invoke a command shell by default and thus prevents the execution of injected metacharacters unless explicitly configured to do so, at which point rigorous sanitization is required. Additionally, implementing allowlists for acceptable characters in file paths and options can further reduce the attack surface. Organizations relying on this library should assess their exposure by reviewing logs for unusual command patterns or unexpected process executions and apply immediate patches once available to prevent exploitation of this critical flaw.