CVE-2020-11026 in WordPress
Summary
by MITRE
In affected versions of WordPress, files with a specially crafted name when uploaded to the Media section can lead to script execution upon accessing the file. This requires an authenticated user with privileges to upload files. This has been patched in version 5.4.1, along with all the previously affected versions via a minor release (5.3.3, 5.2.6, 5.1.5, 5.0.9, 4.9.14, 4.8.13, 4.7.17, 4.6.18, 4.5.21, 4.4.22, 4.3.23, 4.2.27, 4.1.30, 4.0.30, 3.9.31, 3.8.33, 3.7.33).
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Analysis
by VulDB Data Team • 08/30/2025
This vulnerability exists within the WordPress content management system where improperly validated file names during upload operations can lead to remote code execution when the maliciously named file is subsequently accessed. The flaw specifically affects the media handling functionality and requires an authenticated user with file upload privileges to exploit the vulnerability. The issue stems from inadequate input sanitization of file names during the upload process, allowing specially crafted filenames to bypass security checks and potentially execute malicious scripts when the file is accessed through the web server.
The technical implementation of this vulnerability involves the manipulation of file naming conventions to exploit how WordPress processes and serves media files. When a user uploads a file with a maliciously constructed name, the system fails to properly validate or sanitize the filename before storing it in the media library. This allows attackers to create filenames that could potentially be interpreted as executable scripts or that could trigger unintended behavior in the web server's file handling mechanisms. The vulnerability is particularly concerning because it requires minimal privileges beyond standard user authentication, making it accessible to users with basic upload capabilities.
The operational impact of this vulnerability extends beyond simple file upload functionality and represents a significant security risk for WordPress installations. Attackers could potentially leverage this vulnerability to execute arbitrary code on vulnerable systems, potentially leading to complete system compromise. The vulnerability affects multiple versions of WordPress spanning several major releases, indicating a widespread exposure that required coordinated patching across different version lines. Organizations running affected WordPress versions face elevated risk of unauthorized access and potential data breaches, particularly in environments where users with upload privileges exist.
Mitigation strategies for this vulnerability include immediate deployment of the patched versions released by WordPress, specifically version 5.4.1 and the corresponding minor releases for older versions. System administrators should implement comprehensive security monitoring to detect unauthorized file uploads and access patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-77 and CWE-20 categories related to command injection and input validation failures, and corresponds to attack patterns in the MITRE ATT&CK framework under the T1190 and T1059 techniques for exploitation and execution. Organizations should also consider implementing additional security controls such as file type restrictions, content validation, and network-based monitoring to provide defense-in-depth against similar vulnerabilities.