diff --git a/changelog.d/4165.misc b/changelog.d/4165.misc
new file mode 100644
index 0000000000000000000000000000000000000000..415d80aeab08cc2267d49e99fed00bc6383f4595
--- /dev/null
+++ b/changelog.d/4165.misc
@@ -0,0 +1 @@
+Drop incoming events from federation for unknown rooms