CVE-2016-15033 in Delete All Comments Plugin
Summary
by MITRE • 06/07/2023
The Delete All Comments plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the via the delete-all-comments.php file in versions up to, and including, 2.0. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected sites server which may make remote code execution possible.
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Analysis
by VulDB Data Team • 04/09/2026
The vulnerability identified as CVE-2016-15033 affects the Delete All Comments plugin for WordPress, representing a critical security flaw that undermines the integrity of affected web applications. This issue stems from insufficient input validation mechanisms within the plugin's file handling processes, specifically within the delete-all-comments.php component. The vulnerability exists in versions up to and including 2.0, making a significant portion of WordPress installations susceptible to exploitation. The flaw allows unauthenticated attackers to bypass normal security restrictions and upload malicious files to the target server, creating a severe attack surface that can be leveraged for further compromise.
The technical implementation of this vulnerability resides in the absence of proper file type validation checks within the plugin's upload functionality. When users attempt to perform comment deletion operations, the plugin fails to validate the file extensions or content types of uploaded files, creating a path for attackers to submit malicious payloads. This missing validation mechanism directly violates security best practices and represents a classic example of insecure file upload vulnerabilities that fall under the CWE-434 category. The vulnerability enables attackers to upload files with extensions such as .php, .asp, or other executable formats that can be executed on the web server, potentially allowing for remote code execution and complete system compromise.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads, creating a potential gateway for sophisticated attack chains that can lead to full system compromise. Attackers can exploit this flaw to upload web shells, malware, or other malicious payloads that persist on the compromised server. The unauthenticated nature of the attack means that any visitor to the affected website can potentially exploit this vulnerability without requiring valid credentials or administrative privileges. This makes the vulnerability particularly dangerous as it can be exploited at scale and remains undetected for extended periods, allowing attackers to establish persistent access and maintain control over compromised systems.
Mitigation strategies for CVE-2016-15033 should prioritize immediate plugin updates to versions that address the file validation issues, as well as implementing additional security layers to protect against similar vulnerabilities. Organizations should conduct comprehensive security assessments of their WordPress installations to identify other plugins with similar validation flaws, as this represents a broader pattern of insecure coding practices within the WordPress ecosystem. The vulnerability aligns with several ATT&CK tactics including initial access through web application attacks and privilege escalation via malicious file execution. Security measures should include implementing proper file type validation, restricting file upload directories, and deploying web application firewalls that can detect and block suspicious upload attempts. Regular security audits and vulnerability scanning should be performed to identify and remediate similar issues across all web applications and plugins in use.