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Cross-origin resource sharing (CORS)

Cross-origin resource sharing (CORS) is a mechanism that allows restricted resources on a web page to be accessed from another domain outside the domain from which the first resource was served. CORS also relies on a mechanism by which browsers make a "preflight" request to the server hosting the cross-origin resource, in order to check that the server will permit the actual request. In that preflight, the browser sends headers that indicate the HTTP method and headers that will be used in the actual request. For security reasons, browsers restrict cross-origin HTTP requests initiated from scripts. For example, fetch() and XMLHttpRequest follow the same-origin policy. This means that a web application using those APIs can only request resources from the same origin the application was loaded from unless the response from other origins includes the right CORS headers.

Resource types

  • Invocations of fetch() or XMLHttpRequest
  • Web Fonts (for cross-domain font usage in @font-face within CSS), so that servers can deploy TrueType fonts that can only be loaded cross-origin and used by websites that are permitted to do so
  • WebGL textures
  • Images/video frames drawn to a canvas using drawImage()
  • CSS shapes from images
  • scripts
  • iframes

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MicroWebSrv2

The last Micro Web Server for IoTs (MicroPython) or large servers (CPython), that supports WebSockets, routes, template engine and with really optimized architecture (mem allocations, async I/Os). Ready for ESP32, STM32 on Pyboard, Pycom's chipsets (WiPy, LoPy, ...). Robust, efficient and documented!

  • Updated Apr 2, 2024
  • Python

The CORS Vulnerability Checker is a Python script designed to detect Cross-Origin Resource Sharing (CORS) vulnerabilities in web applications. CORS vulnerabilities occur when a web application's access control policies are misconfigured, allowing malicious websites to make unauthorized requests to the application's resources.

  • Updated Feb 28, 2024
  • Python

Created by WHATWG, Matt Oshry, Brad Porter, Michael Bodell, Tellme Networks

Released May 2006

Followers
12 followers
Website
fetch.spec.whatwg.org/#http-cors-protocol
Wikipedia
Wikipedia

Related Topics

ajax content-security-policy jsonp xhr