diff --git a/libavfilter/f_metadata.c b/libavfilter/f_metadata.c
index 97e5c669fe..2ed1393cba 100644
--- a/libavfilter/f_metadata.c
+++ b/libavfilter/f_metadata.c
@@ -283,6 +283,8 @@ static av_cold void uninit(AVFilterContext *ctx)
 {
     MetadataContext *s = ctx->priv;
 
+    av_expr_free(s->expr);
+    s->expr = NULL;
     if (s->avio_context) {
         avio_closep(&s->avio_context);
     }