CVE-2025-27774 in Applio
Summary
by MITRE • 03/19/2025
Applio is a voice conversion tool. Versions 3.2.7 and prior are vulnerable to server-side request forgery (SSRF) and file write in `model_download.py` (line 156 in 3.2.7). The blind SSRF allows for sending requests on behalf of Applio server and can be leveraged to probe for other vulnerabilities on the server itself or on other back-end systems on the internal network, that the Applio server can reach. The blind SSRF can also be coupled with the an arbitrary file read (e.g., CVE-2025-27784) to read files from hosts on the internal network, that the Applio server can reach, which would make it a full SSRF. The file write allows for writing files on the server, which can be coupled with other vulnerabilities, for example an unsafe deserialization, to achieve remote code execution on the Applio server. As of time of publication, no known patches are available.
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Analysis
by VulDB Data Team • 08/01/2025
The vulnerability identified as CVE-2025-27774 affects Applio, a voice conversion tool, specifically versions 3.2.7 and earlier. This issue stems from insufficient input validation within the model_download.py file, particularly around line 156 in version 3.2.7, creating a dangerous combination of server-side request forgery and arbitrary file write capabilities that fundamentally compromise the security posture of affected systems. The vulnerability manifests through a blind server-side request forgery flaw that enables remote attackers to make HTTP requests from the Applio server's perspective, effectively allowing them to probe internal network resources and potentially identify additional vulnerabilities within the server's environment or connected back-end systems.
The technical implementation of this vulnerability involves the application's failure to properly validate user-supplied input when processing model download requests, creating an attack surface where external actors can manipulate the application's behavior to make requests to internal systems. This blind SSRF capability represents a significant risk as it allows attackers to perform reconnaissance on internal network infrastructure that the Applio server can access, potentially revealing sensitive systems, services, or vulnerabilities that would otherwise remain hidden from external network scanning. The vulnerability's classification aligns with CWE-918, which specifically addresses server-side request forgery vulnerabilities, and demonstrates how such flaws can be leveraged for network reconnaissance and privilege escalation.
The operational impact of this vulnerability extends beyond simple reconnaissance through the inclusion of an arbitrary file write capability that significantly amplifies the threat model. When combined with the SSRF vulnerability, attackers can write malicious files to the Applio server's filesystem, potentially enabling more sophisticated attack vectors such as unsafe deserialization exploits or web shell deployment. This dual nature of the vulnerability creates a pathway for remote code execution, as the file write capability can be used to place malicious payloads that will be executed by the application or system processes. The combination of these vulnerabilities creates a complete attack chain that can lead to full system compromise, making this a critical security issue that requires immediate attention.
Security practitioners should note that this vulnerability's exploitation potential is further enhanced by its relationship to CVE-2025-27784, which represents an arbitrary file read vulnerability that can be combined with the SSRF to create a full SSRF attack vector. The attack surface is particularly concerning because it allows for reading files from internal network hosts that the Applio server can reach, effectively bypassing network segmentation and providing attackers with access to potentially sensitive internal files or system information. The absence of available patches at the time of publication creates an urgent need for immediate mitigation strategies including network segmentation, input validation enforcement, and application firewall rules to prevent exploitation attempts. Organizations should implement restrictive network policies that limit the Applio server's access to internal resources, deploy web application firewalls to monitor and block suspicious requests, and consider temporary application disablement until proper security patches are available to address this critical vulnerability. The ATT&CK framework classification for this vulnerability would include techniques such as T1190 for server-side request forgery and T1059 for command and script injection, with potential progression to T1078 for legitimate credentials usage and T1566 for social engineering components if exploitation leads to credential compromise.