CVE-2021-4382 in Recently Plugin
Summary
by MITRE • 06/07/2023
The Recently plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the fetch_external_image() function in versions up to, and including, 3.0.4. This makes it possible for authenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
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Analysis
by VulDB Data Team • 04/09/2026
The recently plugin for wordpress represents a widely used functionality that allows administrators to display recently published posts or media items on their websites. This plugin operates by fetching external images and storing them locally within the wordpress environment. The vulnerability identified in version 3.0.4 and earlier stems from a critical flaw in the fetch_external_image() function which lacks proper validation of file types during the upload process. This function is designed to retrieve images from external sources and store them within the wordpress installation, but it fails to adequately verify the nature of the files being uploaded, creating a pathway for malicious actors to exploit the system.
The technical flaw manifests through insufficient input validation mechanisms within the plugin's core functionality. When the fetch_external_image() function processes external image requests, it does not properly validate the file extensions or content types of the retrieved media. This omission allows attackers who have authenticated access to the wordpress system to manipulate the upload process and submit files with potentially malicious extensions such as php, aspx, or other server-side executable formats. The vulnerability maps directly to CWE-434 which defines insecure file upload vulnerabilities where applications accept files without proper validation of their content or type. The absence of file type checking creates a direct pathway for attackers to bypass normal security restrictions that would typically prevent execution of server-side scripts.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads and creates significant risk for affected wordpress installations. Authenticated attackers with access to the wordpress admin interface or user accounts can leverage this vulnerability to upload malicious files that could enable remote code execution on the target server. This capability allows adversaries to gain persistent access to the compromised system, potentially leading to full server compromise, data exfiltration, or the establishment of backdoors. The vulnerability affects any wordpress installation running the recently plugin version 3.0.4 or earlier, making it particularly dangerous as it impacts a substantial portion of wordpress users who may not have updated their plugins. The risk is amplified because the attacker only needs authenticated access rather than exploiting a separate authentication bypass vulnerability.
Mitigation strategies for this vulnerability require immediate action from wordpress administrators to update to the patched version of the recently plugin. The fix implemented in newer versions addresses the core validation issue by adding proper file type checking mechanisms that prevent the upload of executable files or scripts. Organizations should also implement additional security measures including restricting file upload capabilities, implementing web application firewalls that can detect and block suspicious file upload attempts, and conducting regular security audits of installed plugins. The ATT&CK framework categorizes this vulnerability under T1190 - Exploit Public-Facing Application which represents the techniques used by adversaries to exploit vulnerabilities in externally accessible applications. Security teams should monitor for suspicious file upload activities and implement automated scanning solutions that can detect potentially malicious files being uploaded through wordpress plugins. Regular patch management procedures should be enforced to ensure all wordpress components remain updated with the latest security fixes and that administrators maintain awareness of plugin vulnerabilities through security advisories and monitoring services.