Cors Misconfiguration Scanner
Fast, accurate and free online cors misconfiguration scanner tool running directly in your browser.
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CORS Misconfiguration Scanner
This tool sends an HTTP(S) request to the specified URL with an Origin header and analyzes the CORS response (Access-Control-Allow-Origin, credentials, methods, and more). It helps detect overly broad settings (such as * or trust in external domains) and assesses whether the configuration could be used in XSS/CSRF/API scenarios. Use it only to audit your own services or services where you have formal permission.
Analysis scope
No obvious misconfigurations were detected from the CORS headers. Remember that this is a quick heuristic test and does not replace a full application audit.
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Other tools you may find usefulCORS Misconfiguration Scanner online - a quick test of CORS headers for your API
Better visibility of API behavior
The tool shows not only what a server responds to, but also how that server treats a given origin and whether it differentiates responses depending on the source of the request, which is crucial to understanding whether CORS configuration is intentional or accidental.
Support for security teams and developers
CORS Misconfiguration Scanner is readable to both people from security teams and developers, making it easier to find a compromise between the convenience of integration and a reasonable level of resource protection, without the need to manually analyze each configuration separately.
How to use the tool step by step
The scanner interface is designed in such a way that it is possible to enter the address of the resource, run the test and read the results with virtually no preparation, while at the same time technical people have access to the raw headers and key parameters of the response if they want to go deeper into the analysis.
- In the URL field, enter the API endpoint or HTTP or HTTPS resource that you want to check for CORS, for example
https://api.yourdomain.pl/v1/usersor a specific panel address. - If you want, change the response timeout to match the performance of the tested system, keeping the limits set in the tool to avoid queries hanging for a very long time.
- Decide whether you want to send the
Origin header- by default this option is enabled, which allows you to see how the server responds to a specific client domain, for example a single page front-end application or a test domain. - Enter the test Origin address if you do not want to use the default value, and click the button to run the scan, and the tool will send the required queries and prepare a report on the same page.
- Review the summary, CORS headers, and the list of detected issues, then forward the results to the appropriate person on your team or use them as a starting point for further manual application security testing.
Examples of issues that the CORS Scanner can detect
The CORS Misconfiguration Scanner report is based on specific rules that analyze the combination of various headers and the server's response, so in practice you will see not only information about what header was set, but also a simple interpretation of what it may mean from a security perspective.
Common high-level warnings and errors
- Setting
Access-Control-Allow-Origin: *withAccess-Control-Allow-Credentials: true, which in many cases is considered very risky because any domain may try to use the resource using browser cookies. - Reflecting the
Origin headerin theAccess-Control-Allow-Originheader for external domains, which may indicate trust in foreign web applications that should not necessarily have full access to the API. - Configurations in which the server opens the list of methods or custom headers wide while still interoperating with applications running on other domains.
Lower level information and warnings
- CORS with credentials enabled only for the same origin, which is often acceptable, but it is still worth being aware of how exactly browser-side protection works.
- Information that the API works via HTTP instead of HTTPS, which is not a CORS error in itself, but has a huge impact on the confidentiality of transmitted data and cookie security.
- Indication that the CORS configuration was detected with no obvious errors, but it is still recommended to test other header and method combinations during a full security test.
Raw Headers Preview and HTTP Details
If you want to analyze the server response yourself, at the bottom of the report you will find a raw HTTP response headers section where you can see the full content of the header packet as returned by the server, which is especially useful for those with experience in application testing and backend integrations.
The summary also includes the final address after redirection, the response status, and the IP address that was the final destination of the query, which helps you understand whether the traffic went exactly where expected, or whether additional layers such as proxies, load balancers, or application firewalls were operating along the way.
Safe and responsible use of the tool
CORS Misconfiguration Scanner is a defensive tool designed for administrators, developers and security specialists who need to quickly check the CORS configuration on their websites, and not for people who would like to exploit errors on the side of other entities.
Remember that testing other people's systems without consent is unethical at best, and may be illegal in many jurisdictions, so only use the scanner where you have permission and use it as a convenient way to detect configuration errors early before they are noticed by third parties.
Frequently asked questions about the CORS configuration scanner
Can I use CORS Misconfiguration Scanner for any page on the Internet
The tool technically allows you to send an HTTP or HTTPS query to a given address, but in accordance with good security practices it is to be used only for websites that belong to you or whose owner has given you explicit consent to carry out tests, so we recommend limiting yourself to your own APIs, administration panels and test environments.
Which means that the tool detected the CORS configuration without obvious errors
If the report shows the CORS configuration without obvious errors, it only means that based on the prepared rules, no popular, known problems were noticed, such as wildcard connected to credentials or mindless trust in foreign domains, but it is not a formal security audit of the full application code, but only an auxiliary analysis of the server's behavior from the browser's perspective.
Should I treat the scan result as a final assessment of the security of my API
No, the CORS scanner is one of many tools you can use when working on security, so it is worth combining its results with automated tests, a review of server configuration, log analysis and, if possible, with an independent security audit or penetration testing performed by specialists.
Test your CORS configuration in seconds
Enter the URL, select test origin, click scan and see how your API responds to browser queries before someone else does.