CVE-2026-107704 in image_optimizer
Summary
by MITRE • 10/08/2026
The image_optimizer Ruby gem 1.3.0 through 1.9.0 contains an OS command injection vulnerability in ImageOptimizer#identify_format that allows attackers to execute commands by supplying a crafted image path when the identify option is enabled. Attackers controlling the path, such as an uploaded file name, can append shell metacharacters like ';' that are executed via Ruby backticks with the Ruby process privileges.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/08/2026
The vulnerability identified in ImageOptimizer versions 1.3.0 through 1.9.0 represents a critical OS command injection flaw located within the identify_format method of the gem. This security defect arises from improper neutralization of special elements used in operating system commands, specifically when the library processes image metadata to determine file format. The core technical issue stems from the use of Ruby backticks or similar shell execution mechanisms that directly incorporate user-supplied input into command strings without adequate sanitization. When an attacker controls the path provided for identification, such as through a manipulated uploaded filename, they can inject arbitrary shell metacharacters like semicolons or pipes. These characters allow the injection of additional commands that are executed by the Ruby process with whatever privileges the application holds at runtime.
From a technical perspective, this vulnerability is classified under CWE-78 Improper Neutralization of Special Elements used in an OS Command and aligns with ATT&CK technique T1059 Command and Scripting Interpreter within the Execution tactic. The attack vector typically involves supplying a maliciously crafted filename during file upload or processing operations where the ImageOptimizer gem attempts to identify the image format using system utilities like ImageMagick's identify command. Because the input is not properly escaped, an attacker can terminate the intended command string and append new commands. For example, if the application constructs a shell call such as "identify #{filename}", providing a filename of "; rm -rf /" would result in the execution of both the identification task and the destructive removal of files depending on system permissions.
The operational impact of this vulnerability is severe, potentially leading to complete compromise of the underlying server or container environment. Since Ruby backticks execute commands with the privileges of the running process, an attacker can achieve remote code execution if the web application runs as a privileged user such as root or www-data. This could result in unauthorized access to sensitive data, modification or deletion of critical system files, installation of persistent backdoors, and lateral movement within the network infrastructure. In cloud-native environments where containers may have elevated privileges due to misconfigurations, this vulnerability can facilitate container escape, further expanding the blast radius of the initial compromise.
Mitigation strategies must focus on immediate remediation through version updates and defensive coding practices. The primary recommendation is to upgrade the ImageOptimizer gem to a patched version that addresses this command injection flaw by properly escaping or validating input before passing it to system commands. If upgrading is not immediately feasible, developers should implement strict allow-listing for file extensions rather than relying on content-based identification via shell commands. Alternatively, using native Ruby libraries such as MiniMagick with safe API methods instead of direct shell execution can significantly reduce the attack surface. Input validation should also be enforced at multiple layers to ensure that only expected alphanumeric characters and standard path separators are accepted in filenames used for image processing operations.