diff --git a/libavcodec/sunrast.c b/libavcodec/sunrast.c
index baf184968f..98bc4ffa63 100644
--- a/libavcodec/sunrast.c
+++ b/libavcodec/sunrast.c
@@ -100,14 +100,14 @@ static int sunrast_decode_frame(AVCodecContext *avctx, void *data,
     if (ret < 0)
         return ret;
 
+    if (buf_end - buf < maplength)
+        return AVERROR_INVALIDDATA;
+
     if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
         return ret;
 
     p->pict_type = AV_PICTURE_TYPE_I;
 
-    if (buf_end - buf < maplength)
-        return AVERROR_INVALIDDATA;
-
     if (depth > 8 && maplength) {
         av_log(avctx, AV_LOG_WARNING, "useless colormap found or file is corrupted, trying to recover\n");