CVE-2025-48889 Overview
CVE-2025-48889 is a high-severity arbitrary file copy vulnerability discovered in Gradio, an open-source Python package widely used for building demos and web applications for machine learning models, APIs, and arbitrary Python functions. The vulnerability exists in Gradio's flagging feature and allows unauthenticated attackers to copy any readable file from the server's filesystem. While the copied files cannot be directly read by attackers, this vulnerability can be exploited to cause a Denial of Service (DoS) condition by copying large files (such as /dev/urandom) to fill available disk space on the target server.
Critical Impact
Unauthenticated attackers can exploit the flagging feature to copy arbitrary files, enabling disk space exhaustion attacks that can render Gradio applications and their host servers inoperable.
Affected Products
- Gradio versions prior to 5.31.0
- Gradio Python package (all platforms)
- Machine learning applications and demos built using vulnerable Gradio versions
Discovery Timeline
- 2025-05-30 - CVE CVE-2025-48889 published to NVD
- 2025-08-26 - Last updated in NVD database
Technical Details for CVE-2025-48889
Vulnerability Analysis
The vulnerability resides in Gradio's flagging feature, which is designed to allow users to flag specific inputs and outputs for review. The flaw stems from improper validation of file paths within this feature, enabling unauthenticated users to specify arbitrary file paths on the server's filesystem. When exploited, the application copies the specified file without proper authorization checks or path sanitization.
The vulnerability is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type), though in this case it manifests as an unrestricted file copy operation. The attack can be executed over the network without any authentication or user interaction, making it particularly dangerous for publicly accessible Gradio deployments.
Root Cause
The root cause of CVE-2025-48889 is insufficient input validation and access control in the flagging feature's file handling mechanism. The application fails to properly validate and restrict the source file paths that can be specified during the flagging operation. This allows attackers to reference files outside the intended application directory, including sensitive system files and special device files like /dev/urandom that can generate infinite data streams.
Attack Vector
The attack vector is network-based and requires no authentication or privileges. An attacker can exploit this vulnerability by sending specially crafted requests to a vulnerable Gradio application's flagging endpoint. The attack sequence involves:
- Identifying a Gradio application running a version prior to 5.31.0
- Crafting a request to the flagging feature that specifies an arbitrary file path
- The server copies the specified file to the flagging directory
- For DoS attacks, repeatedly specifying large files or device files like /dev/urandom to exhaust disk space
The vulnerability mechanism works by exploiting the lack of path validation in the flagging feature. When a user flags content, the application processes file references without verifying that the source path is within expected boundaries. An attacker can manipulate this to reference any readable file on the system. By targeting special files like /dev/urandom, which produces an infinite stream of random data, the attacker can cause the server's disk to fill completely, resulting in service disruption. For detailed technical information, refer to the GitHub Security Advisory.
Detection Methods for CVE-2025-48889
Indicators of Compromise
- Unusual disk space consumption on servers hosting Gradio applications
- Large or numerous files appearing in Gradio's flagging directories
- Files in flagging directories that reference system paths like /dev/urandom, /dev/zero, or /proc/ entries
- Rapid disk I/O activity associated with the Gradio process
Detection Strategies
- Monitor web server access logs for unusual patterns of requests to Gradio flagging endpoints
- Implement file integrity monitoring on Gradio's flagging directories to detect unexpected file creation
- Set up alerts for disk usage thresholds on systems hosting Gradio applications
- Review Gradio application logs for file copy operations referencing system paths outside the application directory
Monitoring Recommendations
- Configure disk space monitoring with alerts at 80% and 90% capacity thresholds
- Implement rate limiting on flagging feature endpoints to slow potential exploitation attempts
- Monitor process resource usage for the Gradio application to detect abnormal disk write activity
- Enable verbose logging for the Gradio application to capture file operation details
How to Mitigate CVE-2025-48889
Immediate Actions Required
- Upgrade all Gradio installations to version 5.31.0 or later immediately
- Audit existing Gradio deployments to identify any running vulnerable versions
- Review flagging directories for any suspicious files that may indicate prior exploitation
- Consider temporarily disabling the flagging feature on public-facing Gradio applications until patching is complete
Patch Information
The vulnerability has been patched in Gradio version 5.31.0. Organizations should update their Gradio installations by running pip install --upgrade gradio to obtain the fixed version. The patch addresses the file path validation issue in the flagging feature to prevent arbitrary file copy operations. For additional details about the fix, see the GitHub Security Advisory.
Workarounds
- Restrict network access to Gradio applications using firewall rules or VPN requirements until patching is complete
- Disable the flagging feature if it is not essential to your application's functionality
- Implement disk quotas on the filesystem used by Gradio's flagging directories to limit potential DoS impact
- Deploy Gradio applications in containerized environments with limited filesystem access and disk space allocation
# Upgrade Gradio to patched version
pip install --upgrade gradio>=5.31.0
# Verify installed version
pip show gradio | grep Version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
