CVE-2026-1306 in midi-Synth Plugin
Summary
by MITRE • 02/14/2026
The midi-Synth plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type and file extension validation in the 'export' AJAX action in all versions up to, and including, 1.1.0. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible granted the attacker can obtain a valid nonce. The nonce is exposed in frontend JavaScript making it trivially accessible to unauthenticated attackers.
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Analysis
by VulDB Data Team • 02/19/2026
The midi-Synth plugin for WordPress represents a significant security vulnerability classified as CVE-2026-1306, which stems from inadequate input validation mechanisms within its export functionality. This flaw exists in all versions up to and including 1.1.0, creating a persistent risk for WordPress installations that utilize this plugin. The vulnerability specifically targets the 'export' AJAX action where the plugin fails to implement proper file type and extension validation checks, allowing attackers to bypass security measures designed to restrict file uploads to legitimate media formats.
The technical implementation of this vulnerability demonstrates a critical failure in the plugin's security architecture, where the absence of file validation creates an unrestricted upload pathway that can be exploited by unauthenticated attackers. This flaw operates at the core of web application security principles, as it violates fundamental access control mechanisms that should prevent unauthorized file operations. The vulnerability aligns with CWE-434, which describes insecure file upload vulnerabilities where applications accept files without proper validation of their type, size, or content, making it particularly dangerous for web applications that process user-supplied data.
The operational impact of CVE-2026-1306 extends beyond simple unauthorized file uploads, as it creates a potential pathway for remote code execution when combined with the exposure of valid nonces in frontend JavaScript. The nonce exposure represents a secondary vulnerability that significantly reduces the attack surface complexity, as attackers can trivially obtain the necessary authentication tokens required to execute the upload functionality. This dual vulnerability creates a particularly dangerous scenario where the combination of unrestricted file upload and exposed authentication tokens enables attackers to establish persistent access to affected systems. The attack vector follows patterns consistent with ATT&CK technique T1566, which involves the exploitation of vulnerabilities in web applications to gain initial access through file upload mechanisms.
The implications of this vulnerability are particularly severe for WordPress environments, as it can lead to complete system compromise when attackers leverage the exposed nonce to execute malicious payloads. The plugin's architecture fails to implement proper input sanitization and validation controls that should be standard in any secure web application, creating a persistent threat that affects all users of affected versions. Organizations running WordPress sites with this plugin face significant risk of data breaches, system compromise, and potential use as a foothold for further attacks within their network infrastructure. The vulnerability's classification as a critical security flaw emphasizes the urgency of immediate remediation efforts to prevent exploitation.
Mitigation strategies for CVE-2026-1306 must address both the immediate file upload vulnerability and the exposed nonce issue. The primary remediation involves upgrading to a patched version of the midi-Synth plugin that implements proper file validation and nonce protection mechanisms. Security administrators should also consider implementing additional protective measures such as web application firewalls that can detect and block suspicious file upload attempts, and network-level controls that monitor for unusual file upload patterns. Organizations should conduct comprehensive security assessments of their WordPress installations to identify other potentially vulnerable plugins and ensure that all security patches are applied promptly. The vulnerability serves as a reminder of the importance of proper input validation and authentication token management in preventing exploitation of web application flaws.