diff --git a/libavcodec/cngenc.c b/libavcodec/cngenc.c
index 55826c75be..15d1e5b657 100644
--- a/libavcodec/cngenc.c
+++ b/libavcodec/cngenc.c
@@ -111,5 +111,5 @@ const AVCodec ff_comfortnoise_encoder = {
     .close          = cng_encode_close,
     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
                                                      AV_SAMPLE_FMT_NONE },
-    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
 };