README.md: add notes on how to report security issues
diff --git a/README.md b/README.md
index 6c1d635..9fe99d8 100644
--- a/README.md
+++ b/README.md
@@ -76,6 +76,12 @@ on a specific repository, please provide a link to it if possible.
We ask that you not open a GitHub Issue for help, only for bug reports.
+**Reporting Security Issues**
+
+In case you think to have found a security issue with libgit2, please do not
+open a public issue. Instead, you can report the issue to the private mailing
+list [security@libgit2.com](mailto:security@libgit2.com).
+
What It Can Do
==============