CVE-2026-100382 in ExternalData Plugin
Summary
by MITRE • 09/25/2026
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') vulnerability in Wikimedia Foundation Mediawiki - ExternalData Extension allows OS Command Injection.
This issue affects Mediawiki - ExternalData Extension: from * before 3.7.
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Analysis
by VulDB Data Team • 09/25/2026
The identified security flaw represents a critical instance of Improper Neutralization of Special Elements used in an Operating System Command, commonly referred to as OS Command Injection or CWE-78. This vulnerability resides within the Wikimedia Foundation's MediaWiki ExternalData extension, specifically affecting versions prior to 3.7. The core technical deficiency lies in the application's failure to adequately sanitize user-supplied input before it is passed to underlying operating system commands. When an attacker provides maliciously crafted data that includes shell metacharacters or command separators, the vulnerable code interprets these elements as part of the executable instruction set rather than as literal string values. This lack of proper validation allows for the arbitrary execution of OS-level commands with the privileges associated with the web server process, fundamentally breaking the isolation between the application layer and the host operating system.
From an operational perspective, the impact of this vulnerability is severe and multifaceted. An attacker who successfully exploits this flaw can achieve remote code execution on the affected MediaWiki instance. This capability enables a wide range of malicious activities, including but not limited to reading sensitive configuration files such as LocalSettings.php which may contain database credentials or API keys, modifying website content, installing backdoors for persistent access, and pivoting to other systems within the internal network if the web server has broader connectivity permissions. The exploitation does not necessarily require authentication in many configurations of this extension, meaning that unauthenticated remote attackers can leverage this flaw to compromise the integrity, confidentiality, and availability of the wiki platform and its underlying infrastructure.
This vulnerability aligns with several established industry standards for categorization and threat modeling. In terms of Common Weakness Enumeration, it is classified under CWE-78, which covers improper neutralization of special elements used in an OS command. Furthermore, within the MITRE ATT&CK framework, this flaw facilitates techniques associated with Command and Scripting Interpreter abuse, specifically allowing attackers to execute commands via system or shell interfaces (T1059). The exploitation path typically involves injecting payloads through parameters that are directly passed to functions like exec(), system(), or passthru() without sufficient filtering of characters such as semicolons, pipes, ampersands, and backticks.
To mitigate this risk, immediate action is required by administrators managing MediaWiki installations using the ExternalData extension. The primary remediation step is to upgrade the Extension to version 3.7 or later, where these input validation mechanisms have been corrected. If upgrading is not immediately feasible due to compatibility constraints with other plugins or custom code, temporary mitigations should be implemented at the web server level or through application-level patches that strictly whitelist allowed characters for external data parameters and escape all special shell metacharacters before command execution. Additionally, deploying a Web Application Firewall can provide an additional layer of defense by blocking requests containing known OS injection patterns until the software is fully patched. Regular security audits and code reviews focusing on how user input interacts with system-level functions are essential to prevent similar vulnerabilities in future development cycles.