diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 7391a69611..61bf5675f4 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -3405,6 +3405,11 @@ int avpriv_bprint_to_extradata(AVCodecContext *avctx, struct AVBPrint *buf)
     ret = av_bprint_finalize(buf, &str);
     if (ret < 0)
         return ret;
+    if (!av_bprint_is_complete(buf)) {
+        av_free(str);
+        return AVERROR(ENOMEM);
+    }
+
     avctx->extradata = str;
     /* Note: the string is NUL terminated (so extradata can be read as a
      * string), but the ending character is not accounted in the size (in