CVE-2026-48945 in K2 Extension
Summary
by MITRE • 06/25/2026
The K2 article gallery upload path accepts a zip/tar archive, extracts it under `/media/k2/galleries//`, and only renames image files (gif/jpg/jpeg/png/webp) to safe names — non-image files (including `.php`) are extracted as-is and remain executable via direct HTTP access.
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Analysis
by VulDB Data Team • 06/25/2026
This vulnerability represents a critical path traversal and arbitrary code execution flaw within the K2 article gallery component that fundamentally undermines the application's security model through improper file handling during archive extraction processes. The vulnerability stems from insufficient input validation and sanitization of uploaded archive contents, allowing attackers to bypass the intended security controls that only rename image files while leaving all other file types untouched. When a malicious user uploads a zip or tar archive containing PHP files alongside legitimate images, the system extracts all files to the designated gallery directory without proper access control enforcement, creating a scenario where executable code can be directly accessed via HTTP requests.
The technical implementation of this vulnerability aligns with CWE-434 Unrestricted Upload of File with Dangerous Type, which specifically addresses the security risks associated with accepting file uploads without proper validation and sanitization. The flaw operates at the intersection of insecure file handling practices and inadequate privilege separation between different file types within the extracted archive structure. The system's failure to implement proper file type restrictions during extraction means that any file with a .php extension or other executable extensions becomes immediately accessible to remote attackers who can execute arbitrary code on the server through direct HTTP access to the extracted file paths.
From an operational impact perspective, this vulnerability enables attackers to achieve persistent code execution capabilities within the target environment, potentially leading to complete system compromise. The extracted PHP files can be executed directly through HTTP requests without any additional authentication or authorization checks, allowing threat actors to deploy backdoors, steal sensitive data, or establish command and control channels. This vulnerability directly maps to several ATT&CK techniques including T1059 Command and Scripting Interpreter for executing code and T1566 Phishing for initial access, as attackers can leverage this flaw to gain a foothold in the system.
The security implications extend beyond immediate code execution to include potential privilege escalation scenarios where attackers can manipulate the file system to gain elevated privileges or access sensitive configuration files. The vulnerability also creates opportunities for attackers to establish persistent access through the deployment of web shells or other malicious payloads that can survive system reboots and normal operations. Organizations should implement immediate mitigations including strict file type validation during archive extraction, enforcement of proper file permissions on extracted content, and implementation of web application firewalls to detect and block suspicious file access patterns. Additionally, regular security auditing of uploaded content and automated malware scanning should be implemented to prevent exploitation of similar vulnerabilities in other components of the application stack.