CVE-2025-31477: Tauri Plugin-shell RCE Vulnerability

CVE-2025-31477 Overview

CVE-2025-31477 is a critical improper input validation vulnerability in the Tauri shell plugin that allows attackers to bypass protocol restrictions and achieve remote code execution. The Tauri shell plugin exposes functionality to execute code and open programs on the system through its open endpoint, which is designed to work with the system opener (e.g., xdg-open on Linux). While this functionality was intended to be restricted to a reasonable number of protocols like https:// or mailto:// by default, improper validation of allowed protocols rendered these restrictions non-functional.

Critical Impact

Attackers can abuse this vulnerability to open potentially dangerous protocols such as file://, smb://, or nfs:// through the system registered protocol handler, leading to remote code execution on affected systems.

Affected Products

• Tauri plugin-shell versions prior to 2.2.1 (Rust)
• Tauri plugin-shell versions prior to 2.2.1 (Node.js)

Discovery Timeline

• 2025-04-02 - CVE-2025-31477 published to NVD
• 2025-04-29 - Last updated in NVD database

Technical Details for CVE-2025-31477

Vulnerability Analysis

The vulnerability exists in the Tauri shell plugin's open endpoint, which provides functionality to interact with the system's default application handler. The plugin was designed with security controls to limit which URI protocols could be opened, intending to allow only safe protocols like http://, https://, tel:, and mailto://. However, due to improper validation logic in the protocol checking mechanism, these restrictions failed to function as intended.

This flaw allows untrusted user input to be passed to the open endpoint, which then processes potentially dangerous protocols without proper validation. When malicious protocols are processed, they are handed off to the operating system's registered protocol handlers, which can execute arbitrary code or access sensitive resources.

Root Cause

The root cause is classified as CWE-20 (Improper Input Validation). The protocol validation logic in the shell plugin failed to properly enforce the allowlist of safe protocols. The default configuration claimed to restrict access to safe protocols, but the implementation did not correctly validate incoming protocol schemes against this allowlist, allowing arbitrary protocols to pass through unchecked.

Attack Vector

Exploitation of this vulnerability requires either direct exposure of the open endpoint to application users or the ability to execute code in the frontend of a Tauri application. An attacker can craft malicious URIs using dangerous protocols like file://, smb://, or nfs:// and pass them to the vulnerable endpoint. The attack can be executed over the network without requiring authentication or user interaction.

The attack flow involves:

1. Attacker identifies a Tauri application using the vulnerable shell plugin
2. Attacker crafts a malicious URI with a dangerous protocol scheme
3. The URI is passed to the open endpoint through user-controlled input or frontend code execution
4. The plugin fails to validate the protocol and passes it to the system handler
5. The system executes the protocol handler, potentially running arbitrary code

The security patch demonstrates the fix by changing the default permissions:

         }
       ]
     },
-    "shell:allow-open",
+    "shell:default",
     "shell:allow-kill",
     "shell:allow-stdin-write",
     "process:allow-exit",

Source: GitHub Commit Change

The updated default permissions documentation clarifies the intended behavior:

 
 #### Granted Permissions
 
-It allows to use the `open` functionality without any specific
+It allows to use the `open` functionality with a reasonable
 scope pre-configured. It will allow opening `http(s)://`,
 `tel:` and `mailto:` links.
 """

Source: GitHub Commit Change

Detection Methods for CVE-2025-31477

Indicators of Compromise

• Unexpected calls to the shell:allow-open endpoint with non-standard protocol schemes
• System logs showing protocol handler invocations for file://, smb://, nfs://, or other dangerous protocols originating from Tauri applications
• Evidence of remote file system access or network share mounting initiated by application processes

Detection Strategies

• Monitor application logs for URI open requests containing protocols other than http://, https://, tel:, or mailto://
• Implement runtime monitoring for Tauri applications to detect exploitation attempts through the shell plugin
• Review application capability configurations for use of shell:allow-open instead of the more restrictive shell:default permission

Monitoring Recommendations

• Enable verbose logging for Tauri shell plugin operations in production environments
• Monitor network traffic for unusual SMB or NFS connection attempts from application servers
• Implement alerting on file system access patterns that deviate from normal application behavior

How to Mitigate CVE-2025-31477

Immediate Actions Required

• Upgrade Tauri plugin-shell to version 2.2.1 or later immediately
• Audit all Tauri applications using the shell plugin to identify exposure
• Review application capability configurations and replace shell:allow-open with shell:default where applicable
• Restrict user input that could reach the open endpoint until patching is complete

Patch Information

Tauri has released version 2.2.1 of the plugin-shell package which properly enforces protocol validation on the open endpoint. The fix ensures that only safe protocols (http://, https://, tel:, and mailto://) are allowed by default. Organizations should update their dependencies to the patched version as soon as possible.

For detailed patch information, refer to the GitHub Security Advisory and the GitHub Commit Change.

Workarounds

• If immediate patching is not possible, restrict or disable the shell plugin's open functionality entirely
• Implement strict input validation at the application layer to filter dangerous protocol schemes before they reach the plugin
• Use explicit protocol allowlists in application code rather than relying on default plugin restrictions

# Update Tauri plugin-shell to patched version
# For Rust projects using Cargo
cargo update -p tauri-plugin-shell

# For Node.js projects using npm
npm update @tauri-apps/plugin-shell

# Verify the installed version is 2.2.1 or later
cargo tree -p tauri-plugin-shell