If you believe that you have found a vulnerability in OWASP AntiSamy .NET, first please search the GitHub issues list (for both open and closed issues) to see if it has already been reported.

If it has not, then please contact Sebastián Passaro (sebastian.passaro at owasp.org) directly. Please do not report any suspected vulnerabilities via GitHub issues as we wish to keep our users secure while a patch is implemented and deployed. This is because if this is reported as a GitHub issue, it more or less is equivalent to dropping a 0-day on all applications using OWASP AntiSamy .NET. Instead, we encourage responsible disclosure.

If you wish to be acknowledged for finding the vulnerability, then please follow this process. One of the project leaders will try to contact you within at least 5 business days. If you eventually wish to have it published as a CVE, we will also work with you to ensure that you are given proper credit with MITRE and NIST. Even if you do not wish to report the vulnerability as a CVE, we will acknowledge you when we create a GitHub issue (once the issue is patched).

If possible, provide a working proof-of-concept or at least minimally describe how it can be exploited in sufficient details that the OWASP AntiSamy .NET development team can understand what needs to be done to fix it.