CVE-2025-43843 in Retrieval-based-Voice-Conversion-WebUI
Summary
by MITRE • 05/05/2025
Retrieval-based-Voice-Conversion-WebUI is a voice changing framework based on VITS. Versions 2.2.231006 and prior are vulnerable to command injection. The variables exp_dir1, np7 and f0method8 take user input and pass it into the extract_f0_feature function, which concatenates them into a command that is run on the server. This can lead to arbitrary command execution. As of time of publication, no known patches exist.
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Analysis
by VulDB Data Team • 08/01/2025
The vulnerability identified as CVE-2025-43843 affects the Retrieval-based-Voice-Conversion-WebUI framework, a voice conversion system built upon the VITS architecture that enables users to modify vocal characteristics through automated processes. This particular implementation suffers from a critical command injection flaw that stems from improper input validation within its core processing functions. The affected versions encompass all releases up to and including 2.2.231006, making a substantial portion of the user base potentially vulnerable to exploitation. The vulnerability specifically targets three variables named exp_dir1, np7, and f0method8 which are designed to accept user-provided parameters for configuring the voice conversion process. These parameters are subsequently passed into the extract_f0_feature function without adequate sanitization or validation measures, creating a direct pathway for malicious input to be executed as system commands.
The technical exploitation mechanism operates through the concatenation of user-supplied parameters into shell commands that execute on the server hosting the voice conversion framework. When users provide inputs for these variables, the system fails to properly validate or escape the data before incorporating it into command strings that are subsequently executed by the operating system. This design flaw allows an attacker to inject malicious commands that will be interpreted and executed with the privileges of the web server process, potentially leading to complete system compromise. The vulnerability manifests as a classic command injection attack pattern where untrusted input flows directly into a command execution context, representing a fundamental breakdown in input sanitization and output encoding practices. This type of vulnerability is categorized under CWE-78 as "Improper Neutralization of Special Elements used in an OS Command," which specifically addresses the dangerous practice of directly incorporating user input into system commands without proper sanitization.
The operational impact of this vulnerability extends far beyond simple data compromise, as successful exploitation could enable attackers to execute arbitrary code on the affected server with the privileges of the web application user. This capability allows for complete system takeover, data exfiltration, persistent backdoor installation, and potential lateral movement within network environments where the vulnerable system resides. The attack surface is particularly concerning given that voice conversion systems often process user-uploaded audio files, making them attractive targets for malicious actors seeking to establish persistent access points. The vulnerability's severity is amplified by the lack of available patches at the time of publication, leaving affected organizations with no immediate remediation options. Attackers could leverage this weakness to gain unauthorized access to voice processing infrastructure, potentially compromising sensitive audio data or using the system as a pivot point for further network infiltration. The absence of patch availability creates a prolonged window of exposure for organizations relying on these voice conversion frameworks, particularly those in industries handling confidential communications such as healthcare, legal services, or financial institutions.
Organizations utilizing this framework should immediately implement network-level mitigations including firewall rules that restrict access to the voice conversion interface and monitor for suspicious command execution patterns. The recommended defensive strategies encompass input validation at multiple layers, including application-level sanitization of user parameters, implementation of proper command execution frameworks that do not rely on string concatenation, and deployment of web application firewalls to detect and block malicious payloads. Additionally, system administrators should consider implementing principle of least privilege access controls, ensuring that the web application operates with minimal necessary permissions and that sensitive system commands are not directly executable through user input. Security monitoring should focus on identifying anomalous command execution patterns and unusual network traffic originating from the voice conversion service. Organizations should also consider deploying intrusion detection systems capable of recognizing command injection patterns and implementing regular security audits of the voice conversion framework's input handling mechanisms. The ATT&CK framework categorizes this vulnerability under T1059.001 "Command and Scripting Interpreter: PowerShell" and T1059.003 "Command and Scripting Interpreter: Windows Command Shell" as exploitation would involve executing commands through the operating system shell, while the broader technique T1203 "Exploitation for Client Execution" encompasses the overall exploitation process that leverages the command injection vulnerability.