CVE-2025-24010: Vitejs Vite SSRF Vulnerability

CVE-2025-24010 Overview

CVE-2025-24010 is an Origin Validation Error vulnerability affecting Vite, a popular frontend tooling framework for JavaScript. The vulnerability stems from permissive default CORS (Cross-Origin Resource Sharing) settings combined with insufficient validation of the Origin header for WebSocket connections. This flaw allows any malicious website to send arbitrary requests to a Vite development server and read the responses, potentially exposing sensitive source code, configuration files, and development environment data.

Critical Impact

Attackers can leverage this vulnerability to exfiltrate sensitive application source code, environment variables, and configuration data from developers' local machines through malicious websites.

Affected Products

• Vite versions prior to 6.0.9
• Vite versions prior to 5.4.12
• Vite versions prior to 4.5.6

Discovery Timeline

• 2025-01-20 - CVE-2025-24010 published to NVD
• 2025-09-19 - Last updated in NVD database

Technical Details for CVE-2025-24010

Vulnerability Analysis

This vulnerability is classified as CWE-346 (Origin Validation Error), which occurs when a product fails to properly verify that the source of data or communication is valid. In the context of Vite's development server, the issue manifests in two interconnected security weaknesses.

First, the development server's default CORS configuration is overly permissive, allowing cross-origin requests from any domain. Second, and more critically, the WebSocket connection handling lacks proper validation of the Origin header. WebSocket connections are particularly sensitive because they maintain persistent bidirectional communication channels that can bypass traditional CORS protections once established.

When a developer runs Vite's development server locally, a malicious website visited in the same browser can exploit these weaknesses to establish connections to the local development server. The attacker's website can then request and read source files, module contents, and potentially sensitive configuration data that the development server exposes.

Root Cause

The root cause lies in the insufficient security controls for cross-origin access in Vite's HTTP and WebSocket server implementations. The development server was designed with a focus on developer experience and local development convenience, resulting in permissive default settings that assume a trusted network environment. The lack of Origin header validation for WebSocket upgrade requests allows attackers to circumvent the browser's same-origin policy protections.

Attack Vector

The attack requires user interaction—specifically, a developer with an active Vite development server must visit a malicious website. The attacker-controlled website contains JavaScript code that initiates connections to common development server ports (typically localhost:5173 or similar). Because the Vite server does not validate the Origin header, these cross-origin requests succeed.

The malicious website can then request the application's source code, including JavaScript modules, configuration files such as vite.config.js, and potentially environment variable files. The attack exploits the trust developers place in their local development environment, turning the browser into an exfiltration vector.

For detailed technical information about the exploitation mechanism, refer to the GitHub Security Advisory for GHSA-vg6x-rcgg-rjx6.

Detection Methods for CVE-2025-24010

Indicators of Compromise

• Unexpected outbound network connections from the browser to localhost development ports
• Cross-origin WebSocket connection attempts in browser developer tools network logs
• Unusual file access patterns in Vite development server logs from cross-origin sources
• Network traffic analysis showing responses to localhost ports being transmitted to external domains

Detection Strategies

• Monitor browser network activity for WebSocket connections to development server ports originating from external domains
• Implement network monitoring to detect data exfiltration patterns from localhost to external hosts
• Review development server logs for requests containing suspicious or unexpected Origin headers
• Use browser extensions or security tools that alert on cross-origin requests to localhost services

Monitoring Recommendations

• Enable verbose logging on Vite development servers to capture Origin header information
• Deploy endpoint detection tools that monitor for unusual localhost network activity patterns
• Establish baseline network behavior during development to identify anomalous cross-origin communications
• Implement browser-level monitoring for JavaScript attempting to connect to local development ports

How to Mitigate CVE-2025-24010

Immediate Actions Required

• Upgrade Vite to version 6.0.9, 5.4.12, or 4.5.6 or later immediately
• Avoid browsing untrusted websites while running Vite development servers
• Consider using private browsing or separate browser profiles for development work
• Restrict development server access to the loopback interface only

Patch Information

The Vite maintainers have released security patches addressing this vulnerability across all supported major versions. The fixes implement proper Origin header validation for WebSocket connections and tighten the default CORS configuration. Organizations should update to the following patched versions:

• Version 6.0.9 for Vite 6.x users
• Version 5.4.12 for Vite 5.x users
• Version 4.5.6 for Vite 4.x users

For complete details on the security fix, see the Vite Security Advisory.

Workarounds

• Configure the development server to bind only to 127.0.0.1 rather than all interfaces
• Implement a reverse proxy with strict Origin validation in front of the development server
• Use browser isolation by running development browsers in separate profiles or containers
• Consider using a firewall to block external access to development server ports

# Configuration example - restrict Vite server to localhost only
# In vite.config.js, add server configuration:
# server: {
#   host: '127.0.0.1',
#   strictPort: true
# }
# 
# Alternatively, start Vite with host restriction:
npx vite --host 127.0.0.1