CVE-2026-76124 in App Plugin
Summary
by MITRE • 11/03/2026
The BuddyBoss App plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 3.2.1 via the send_feedback function. This is due to insufficient file type validation that relies solely on the client-supplied Content-Type header without server-side content inspection or extension validation. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload files that may be executable, which makes remote code execution possible. While uploaded files are deleted after email transmission, a race condition exists during SMTP execution that allows access to the file, and files persist indefinitely when wp_mail() fails.
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Analysis
by VulDB Data Team • 11/03/2026
The BuddyBoss App plugin for WordPress contains a critical security vulnerability affecting all versions up to and including 3.2.1. This flaw is classified as an Arbitrary File Upload vulnerability, which falls under CWE-434 in the Common Weakness Enumeration standard. The issue resides specifically within the send_feedback function of the application codebase. The root cause of this vulnerability is a fundamental failure in input validation logic regarding file uploads. Instead of implementing robust server-side checks to verify the actual content and extension of uploaded files, the plugin relies exclusively on the client-supplied Content-Type header provided by the HTTP request. This approach is inherently insecure because the Content-Type header can be easily manipulated or spoofed by an attacker using standard web tools or custom scripts. Without performing MIME type sniffing or validating file extensions against a strict allowlist, the application accepts any file that claims to have a valid content type, regardless of its actual binary structure or intent.
This lack of rigorous validation allows authenticated attackers with subscriber-level access and above to bypass security controls and upload malicious files directly to the server's filesystem. Since WordPress plugins typically execute within the context of the web server user, successfully uploading an executable file such as a PHP script provides the attacker with a foothold on the system. If the uploaded file is executed by the web server when accessed via its URL path, it results in Remote Code Execution (RCE). This aligns with MITRE ATT&CK technique T1505.003, which involves Server Side Request Forgery or Web Shell deployment through upload mechanisms. The severity of this vulnerability is significantly amplified because it does not require administrative privileges to exploit; even low-privileged users can achieve full system compromise if they can trigger the vulnerable function and successfully deliver a web shell payload.
The operational impact of this vulnerability extends beyond simple file storage, as it directly threatens the confidentiality, integrity, and availability of the WordPress installation and potentially the underlying host server. An attacker who exploits this flaw can execute arbitrary commands on the server, leading to data exfiltration, defacement, or the establishment of persistent backdoors for future access attempts. Although the plugin's design intent is to delete uploaded files after they are transmitted via email using wp_mail(), a race condition exists during the SMTP execution phase that allows an attacker to access and execute the file before it is deleted. Furthermore, if the mail transmission fails due to server configuration issues or network problems, the malicious file persists indefinitely on the disk. This persistence ensures that even in cases where immediate exploitation via timing might be difficult, the vulnerability remains a long-term threat vector as long as the infected files remain accessible through their web paths.
Mitigation strategies must address both the immediate technical flaw and broader security hygiene practices. The most effective remediation is to upgrade the BuddyBoss App plugin to version 3.2.2 or later, where developers have implemented proper server-side file validation including extension whitelisting and content inspection. For organizations unable to patch immediately due to compatibility constraints, temporary mitigations should include restricting upload capabilities for non-administrative users through WordPress role management settings if possible. Additionally, web application firewalls can be configured to detect and block requests containing suspicious file extensions or malformed Content-Type headers associated with known attack patterns. It is also critical to ensure that the wp_mail function is correctly configured and monitored, as failures in email delivery directly contribute to the persistence of these malicious files. Regular security audits and penetration testing should be conducted to verify that no residual upload vulnerabilities exist within other parts of the application ecosystem.