diff --git a/libavformat/stldec.c b/libavformat/stldec.c
index d6e0713f8c..fb67407ac5 100644
--- a/libavformat/stldec.c
+++ b/libavformat/stldec.c
@@ -97,8 +97,10 @@ static int stl_read_header(AVFormatContext *s)
         if (pts_start != AV_NOPTS_VALUE) {
             AVPacket *sub;
             sub = ff_subtitles_queue_insert(&stl->q, p, strlen(p), 0);
-            if (!sub)
+            if (!sub) {
+                ff_subtitles_queue_clean(&stl->q);
                 return AVERROR(ENOMEM);
+            }
             sub->pos = pos;
             sub->pts = pts_start;
             sub->duration = duration;