diff --git a/libavformat/wavdec.c b/libavformat/wavdec.c
index 98e97878cb..410c2ec1f9 100644
--- a/libavformat/wavdec.c
+++ b/libavformat/wavdec.c
@@ -249,7 +249,7 @@ static int wav_read_header(AVFormatContext *s)
     int64_t size, av_uninit(data_size);
     int64_t sample_count = 0;
     int rf64 = 0;
-    char start_code[5];
+    char start_code[32];
     uint32_t tag;
     AVIOContext *pb      = s->pb;
     AVStream *st         = NULL;
@@ -273,7 +273,7 @@ static int wav_read_header(AVFormatContext *s)
         rf64 = 1;
         break;
     default:
-        av_get_codec_tag_string(start_code, 5, tag);
+        av_get_codec_tag_string(start_code, sizeof(start_code), tag);
         av_log(s, AV_LOG_ERROR, "invalid start code %s in RIFF header\n", start_code);
         return AVERROR_INVALIDDATA;
     }