diff --git a/src/cluster/backend/zeromq/ZeroMQ.cc b/src/cluster/backend/zeromq/ZeroMQ.cc
index a695a24f7b..ef117749ac 100644
--- a/src/cluster/backend/zeromq/ZeroMQ.cc
+++ b/src/cluster/backend/zeromq/ZeroMQ.cc
@@ -297,7 +297,7 @@ bool ZeroMQBackend::DoUnsubscribe(const std::string& topic_prefix) {
     try {
         // Prepend 0x00 byte to indicate subscription to XSUB socket.
         // This is the XSUB API instead of setsockopt(ZMQ_SUBSCRIBE).
-        std::string msg = "\x00" + topic_prefix;
+        std::string msg = '\0' + topic_prefix;
         main_inproc.send(zmq::const_buffer(msg.data(), msg.size()));
     } catch ( zmq::error_t& err ) {
         zeek::reporter->Error("Failed to unsubscribe from topic %s: %s", topic_prefix.c_str(), err.what());
diff --git a/testing/btest/Baseline/cluster.zeromq.unsubscribe/..manager.out b/testing/btest/Baseline/cluster.zeromq.unsubscribe/..manager.out
new file mode 100644
index 0000000000..31e6e4aeaf
--- /dev/null
+++ b/testing/btest/Baseline/cluster.zeromq.unsubscribe/..manager.out
@@ -0,0 +1,5 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+node_up, worker-1
+subscription, /test/worker/topic
+unsubscription, /test/worker/topic
+node_down, worker-1
diff --git a/testing/btest/Baseline/cluster.zeromq.unsubscribe/..worker.out b/testing/btest/Baseline/cluster.zeromq.unsubscribe/..worker.out
new file mode 100644
index 0000000000..e265cc3e2a
--- /dev/null
+++ b/testing/btest/Baseline/cluster.zeromq.unsubscribe/..worker.out
@@ -0,0 +1,5 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+start_test
+subscription, /test/manager/topic
+unsubscription, /test/manager/topic
+done
diff --git a/testing/btest/cluster/zeromq/unsubscribe.zeek b/testing/btest/cluster/zeromq/unsubscribe.zeek
new file mode 100644
index 0000000000..1067465bfd
--- /dev/null
+++ b/testing/btest/cluster/zeromq/unsubscribe.zeek
@@ -0,0 +1,84 @@
+# @TEST-DOC: Regression test for unsubscriptions not actually unsubscribing because of "\x00" usage.
+#
+# @TEST-REQUIRES: have-zeromq
+#
+# @TEST-GROUP: cluster-zeromq
+#
+# @TEST-PORT: XPUB_PORT
+# @TEST-PORT: XSUB_PORT
+# @TEST-PORT: LOG_PULL_PORT
+#
+# @TEST-EXEC: cp $FILES/zeromq/cluster-layout-simple.zeek cluster-layout.zeek
+# @TEST-EXEC: cp $FILES/zeromq/test-bootstrap.zeek zeromq-test-bootstrap.zeek
+#
+# @TEST-EXEC: zeek --parse-only ./manager.zeek ./worker.zeek
+#
+# @TEST-EXEC: btest-bg-run manager "ZEEKPATH=$ZEEKPATH:.. && CLUSTER_NODE=manager zeek -b ../manager.zeek >out"
+# @TEST-EXEC: btest-bg-run worker "ZEEKPATH=$ZEEKPATH:.. && CLUSTER_NODE=worker-1 zeek -b ../worker.zeek >out"
+#
+# @TEST-EXEC: btest-bg-wait 30
+# @TEST-EXEC: btest-diff ./manager/out
+# @TEST-EXEC: btest-diff ./worker/out
+
+
+# @TEST-START-FILE common.zeek
+@load ./zeromq-test-bootstrap
+
+global start_test: event() &is_used;
+
+# @TEST-END-FILE
+
+# @TEST-START-FILE manager.zeek
+@load ./common.zeek
+
+event Cluster::Backend::ZeroMQ::subscription(topic: string) {
+	if ( topic == "/test/worker/topic" ) {
+		print "subscription", topic;
+		Cluster::subscribe("/test/manager/topic");
+	}
+}
+
+event Cluster::Backend::ZeroMQ::unsubscription(topic: string) {
+	if ( topic == "/test/worker/topic" ) {
+		print "unsubscription", topic;
+		Cluster::unsubscribe("/test/manager/topic");
+	}
+}
+
+event Cluster::node_up(name: string, id: string) {
+	print "node_up", name;
+	Cluster::publish(Cluster::nodeid_topic(id), start_test);
+}
+
+event Cluster::node_down(name: string, id: string) {
+	print "node_down", name;
+	terminate();
+}
+# @TEST-END-FILE
+
+# @TEST-START-FILE worker.zeek
+@load ./common.zeek
+
+event start_test() {
+	print "start_test";
+	Cluster::subscribe("/test/worker/topic");
+}
+
+event Cluster::Backend::ZeroMQ::subscription(topic: string) {
+	if ( topic == "/test/manager/topic" ) {
+		print "subscription", topic;
+		Cluster::unsubscribe("/test/worker/topic");
+	}
+}
+
+event Cluster::Backend::ZeroMQ::unsubscription(topic: string) {
+	if ( topic == "/test/manager/topic" ) {
+		print "unsubscription", topic;
+		terminate();
+	}
+}
+
+event zeek_done() {
+	print "done";
+}
+# @TEST-END-FILE