CVE-2021-43831 in Gradio
Summary
by MITRE • 12/15/2021
Gradio is an open source framework for building interactive machine learning models and demos. In versions prior to 2.5.0 there is a vulnerability that affects anyone who creates and publicly shares Gradio interfaces. File paths are not restricted and users who receive a Gradio link can access any files on the host computer if they know the file names or file paths. This is limited only by the host operating system. Paths are opened in read only mode. The problem has been patched in gradio 2.5.0.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-43831 represents a critical access control flaw in the Gradio framework that enables unauthorized file access on affected systems. This issue affects all versions prior to 2.5.0 and specifically targets users who create and publicly share Gradio interfaces, making it particularly dangerous in collaborative or production environments where interfaces might be exposed to external users. The vulnerability stems from inadequate input validation and path restriction mechanisms within the framework's file handling capabilities.
The technical implementation of this flaw allows attackers to exploit the lack of proper path validation by constructing malicious file paths that bypass normal access controls. When users receive a Gradio link, they can potentially access any file on the host computer if they possess knowledge of specific file names or paths, with the only limitations being those imposed by the underlying operating system permissions. This represents a classic path traversal vulnerability that operates at the application level, where the framework fails to properly sanitize or restrict file system access requests. The vulnerability specifically affects read-only file access operations, meaning that even if the attacker cannot modify files directly, they can still extract sensitive information from the system.
The operational impact of CVE-2021-43831 extends beyond simple information disclosure, as it can potentially expose sensitive system files, configuration data, and other confidential information stored on the host machine. This vulnerability is particularly concerning in machine learning environments where Gradio interfaces might contain references to model files, training data, or system configuration details that could be valuable to attackers. The risk is amplified when interfaces are deployed in shared or public environments where multiple users might have access to the same system. According to CWE classification, this vulnerability maps to CWE-22 Path Traversal, which is a well-documented weakness in software systems that allows attackers to access files and directories outside of the intended scope. The attack pattern aligns with techniques described in MITRE ATT&CK framework under T1083 File and Directory Discovery, where adversaries seek to identify and access files on compromised systems.
The remediation for this vulnerability requires upgrading to Gradio version 2.5.0 or later, which implements proper path validation and access restriction mechanisms. Organizations should also consider implementing additional security measures such as network segmentation, access controls, and monitoring of file access patterns to detect potential exploitation attempts. Security practitioners should conduct thorough audits of existing Gradio deployments to identify and patch vulnerable systems, particularly in environments where interfaces are publicly accessible or shared with untrusted users. The patch addresses the root cause by implementing proper input sanitization and restricting file system access to only intended directories and files, thereby preventing the exploitation of path traversal vulnerabilities.