diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c
index fe17b3781a..6d67c079e4 100644
--- a/src/shared/ptyfwd.c
+++ b/src/shared/ptyfwd.c
@@ -572,9 +572,11 @@ int pty_forward_set_priority(PTYForward *f, int64_t priority) {
         int r;
         assert(f);
 
-        r = sd_event_source_set_priority(f->stdin_event_source, priority);
-        if (r < 0)
-                return r;
+        if (f->stdin_event_source) {
+                r = sd_event_source_set_priority(f->stdin_event_source, priority);
+                if (r < 0)
+                        return r;
+        }
 
         r = sd_event_source_set_priority(f->stdout_event_source, priority);
         if (r < 0)