diff --git a/Appendix-A:-Test-Sites.md b/Appendix-A:-Test-Sites.md
index 8a94194..0a23d58 100644
--- a/Appendix-A:-Test-Sites.md
+++ b/Appendix-A:-Test-Sites.md
@@ -55,6 +55,7 @@ If you would like to submit a test page to be added to this list, please post th
 - [Battery](https://pstadler.sh/battery.js/) <sup>1</sup> - **h**ttps://pstadler.sh/battery.js/
 - [Canvas Blocking Detection](https://kkapsner.github.io/CanvasBlocker/test/detectionTest.html) - **h**ttps://kkapsner.github.io/CanvasBlocker/test/detectionTest.html
    * See [Issue 174](https://github.com/ghacksuserjs/ghacks-user.js/issues/174)
+- [CSS Exfil Vulnerability](https://www.mike-gualtieri.com/css-exfil-vulnerability-tester)
 - [CSS History Leak](http://lcamtuf.coredump.cx/yahh/) <sup>2</sup> - **h**ttp://lcamtuf.coredump.cx/yahh/
 - [DNS Leak](https://www.dnsleaktest.com/) - **h**ttps://www.dnsleaktest.com/
 - [DNS Spoofability](https://www.grc.com/dns/dns.htm) - **h**ttps://www.grc.com/dns/dns.htm