diff --git a/doc/Changelog b/doc/Changelog
index 265a34797..e056a4a33 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -5,6 +5,7 @@
 	- pythonmod logs the python error and traceback on failure.
 	- ignore debug python module for test in doxygen output.
 	- review fixes for python module.
+	- Fix #4209: Crash in libunbound when called from getdns.
 
 21 November 2018: Wouter
 	- Scrub NS records from NODATA responses as well.
diff --git a/libunbound/libworker.c b/libunbound/libworker.c
index 065f0a7b1..a886f9a88 100644
--- a/libunbound/libworker.c
+++ b/libunbound/libworker.c
@@ -657,8 +657,8 @@ libworker_event_done_cb(void* arg, int rcode, sldns_buffer* buf,
 			sec = 1;
 		else if(s == sec_status_secure)
 			sec = 2;
-		(*cb)(cb_arg, rcode, (void*)sldns_buffer_begin(buf),
-			(int)sldns_buffer_limit(buf), sec, why_bogus, was_ratelimited);
+		(*cb)(cb_arg, rcode, (buf?(void*)sldns_buffer_begin(buf):NULL),
+			(buf?(int)sldns_buffer_limit(buf):0), sec, why_bogus, was_ratelimited);
 	}
 }