CVE-2026-52891
Summary
by MITRE • 07/16/2026
Wekan is open source kanban built with Meteor. Prior to 9.07, Wekan avatar upload functionality embeds user-supplied filenames into paths later passed to child_process.exec() for MIME-type detection. Because models/avatars.js and models/fileValidation.js used a shell command with the avatar filename, shell metacharacters such as backticks and $() in the filename could execute commands on the server. This issue is fixed in version 9.07.
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Analysis
by VulDB Data Team • 07/16/2026
The vulnerability in Wekan versions prior to 9.07 represents a critical command injection flaw that stems from improper input validation in the avatar upload functionality. This issue occurs within the models/avatars.js and models/fileValidation.js files where user-supplied filenames are directly embedded into shell commands without proper sanitization or escaping mechanisms. The system utilizes child_process.exec() to execute MIME-type detection operations, creating an environment where maliciously crafted filenames can trigger unintended command execution on the server. When attackers upload avatar files containing shell metacharacters such as backticks, parentheses, or dollar signs, these characters are interpreted by the shell and executed with the privileges of the Wekan application process. This vulnerability directly maps to CWE-78 which describes improper neutralization of special elements used in operating system commands, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter. The attack vector is particularly dangerous because it allows remote code execution through seemingly benign file upload functionality, making it accessible to any authenticated user who can submit avatar files.
The operational impact of this vulnerability extends beyond simple command injection, as successful exploitation could enable attackers to gain full control over the Wekan server environment. Attackers could execute arbitrary system commands, access sensitive data, modify application behavior, or even escalate privileges to gain root access depending on the server configuration and permissions granted to the Wekan process. The vulnerability affects all versions prior to 9.07, meaning that organizations running these older releases are potentially exposed to remote code execution attacks. Given that Wekan is an open source collaborative platform typically deployed in enterprise environments, the implications of such a vulnerability are severe as it could compromise entire project management workflows and expose sensitive organizational data. The vulnerability's exploitation requires minimal technical skill since it leverages standard file upload mechanisms that are commonly used by attackers in automated exploitation campaigns.
Mitigation strategies for this vulnerability require immediate patching to version 9.07 or later, which addresses the core issue by properly sanitizing user input before embedding it into shell commands. Organizations should implement comprehensive input validation and sanitization measures that prevent special characters from being interpreted as shell metacharacters. The recommended approach involves using parameterized commands instead of string concatenation, employing dedicated MIME-type detection libraries that do not rely on shell execution, and implementing proper file name sanitization routines that strip or encode dangerous characters. Additionally, organizations should consider implementing network segmentation and access controls to limit the potential impact of successful exploitation. Security monitoring should be enhanced to detect unusual command execution patterns and anomalous file upload activities. The fix aligns with security best practices outlined in OWASP Top 10 2021 category A03: Injection and addresses the principle of least privilege by ensuring that file processing operations are performed with minimal required permissions. Regular security audits and dependency updates should be implemented to prevent similar vulnerabilities from emerging in other components of the Wekan application stack.