diff --git a/src/ui/mucwin.c b/src/ui/mucwin.c
index c508b676..a1a5c850 100644
--- a/src/ui/mucwin.c
+++ b/src/ui/mucwin.c
@@ -737,6 +737,8 @@ mucwin_role_set_error(ProfMucWin *mucwin, const char *const nick, const char *co
 void
 mucwin_info(ProfMucWin *mucwin)
 {
+    assert(mucwin != NULL);
+
     char *role = muc_role_str(mucwin->roomjid);
     char *affiliation = muc_affiliation_str(mucwin->roomjid);