diff --git a/ChangeLog.adoc b/ChangeLog.adoc
index 10f1da713..cb6303347 100644
--- a/ChangeLog.adoc
+++ b/ChangeLog.adoc
@@ -23,6 +23,10 @@ Bug fixes::
 
   * irc: fix display of country code in message 344 received as whois geo info (issue #1736)
 
+Tests::
+
+  * relay: fix crash in tests on Alpine 3.18
+
 Build::
 
   * php: fix detection of PHP 8.2 on Alpine 3.18
diff --git a/src/plugins/relay/irc/relay-irc.c b/src/plugins/relay/irc/relay-irc.c
index 23fe74104..fdc6c79a1 100644
--- a/src/plugins/relay/irc/relay-irc.c
+++ b/src/plugins/relay/irc/relay-irc.c
@@ -206,7 +206,7 @@ relay_irc_sendf (struct t_relay_client *client, const char *format, ...)
     const char *str_message, *ptr_msg1, *ptr_msg2;
     struct t_hashtable *hashtable_in, *hashtable_out;
 
-    if (!client)
+    if (!client || !format)
         return;
 
     weechat_va_format (format);
diff --git a/tests/unit/plugins/relay/irc/test-relay-irc.cpp b/tests/unit/plugins/relay/irc/test-relay-irc.cpp
index b530b3d3b..f1fb2e531 100644
--- a/tests/unit/plugins/relay/irc/test-relay-irc.cpp
+++ b/tests/unit/plugins/relay/irc/test-relay-irc.cpp
@@ -487,7 +487,6 @@ TEST(RelayIrc, RelayIrcMessageParse)
 
 TEST(RelayIrcWithClient, RelayIrcSendf)
 {
-
     relay_irc_sendf (NULL, NULL);
     relay_irc_sendf (NULL, "test");
     relay_irc_sendf (ptr_relay_client, NULL);