CVE-2026-110637 in buildebooks
Summary
by MITRE • 10/14/2026
buildebooks before 0.2.2 contains an OS command injection vulnerability in lib/kindle.js that allows attackers to execute commands by supplying a crafted EPUB file name passed to kindlegen via child_process.exec. Attackers can craft a book project with a malicious front-matter filename or project folder name and kindle: true to execute OS commands as the user running buildebooks.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified in buildebooks versions prior to 0.2.2 represents a critical server-side weakness classified under CWE-78, commonly known as Operating System Command Injection. This flaw resides within the lib/kindle.js module and is triggered during the processing of EPUB files intended for conversion into Kindle-compatible formats using the kindlegen tool. The root cause lies in the improper handling of user-supplied input when constructing system commands. Specifically, the application utilizes Node.js child_process.exec to invoke external binaries, a method that inherently passes command strings directly to the operating system shell without adequate sanitization or validation of special characters and metacharacters.
When an attacker crafts a malicious EPUB file project with specific attributes such as a front-matter filename or a project folder name containing shell injection payloads, these inputs are passed unsanitized into the execution string for kindlegen. Because child_process.exec interprets the entire command line through the system shell (such as /bin/sh on Unix-like systems), an attacker can inject additional commands by exploiting characters like semicolons, ampersands, or pipes within the filename or folder structure. This allows the injection of arbitrary operating system commands that are executed with the privileges of the user account running the buildebooks process.
The operational impact of this vulnerability is severe, as it grants attackers full control over the underlying host environment to the extent permitted by the application's execution context. If buildebooks is run with elevated permissions or if the compromised server hosts other sensitive services, an attacker could potentially exfiltrate data, install backdoors, pivot to internal networks, or disrupt service availability. This aligns with ATT&CK technique T1059, Command and Scripting Interpreter, specifically sub-techniques involving shell commands like sh or bash, which are commonly used in post-exploitation phases for remote access and lateral movement.
Mitigation strategies must focus on eliminating the use of unsafe command execution methods. The primary remediation is to replace child_process.exec with safer alternatives such as child_process.spawn or child_process.execFile, which do not invoke a shell by default and allow arguments to be passed as distinct array elements rather than concatenated strings. Additionally, strict input validation should be implemented for all file names and project paths before they are used in any system operations. This includes enforcing whitelist-based character restrictions that only permit alphanumeric characters, hyphens, underscores, and periods while rejecting shell metacharacters entirely. Upgrading to buildebooks version 0.2.2 or later is essential as it addresses this specific implementation flaw by securing the command construction process against injection attacks.