diff --git a/libavcodec/xl.c b/libavcodec/xl.c
index 1cadeab561..240339ea8b 100644
--- a/libavcodec/xl.c
+++ b/libavcodec/xl.c
@@ -71,6 +71,11 @@ static int decode_frame(AVCodecContext *avctx,
 
     stride = avctx->width - 4;
 
+    if (avctx->width % 4) {
+        av_log(avctx, AV_LOG_ERROR, "Width not a multiple of 4.\n");
+        return AVERROR_INVALIDDATA;
+    }
+
     if (buf_size < avctx->width * avctx->height) {
         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
         return AVERROR_INVALIDDATA;