diff --git a/libavcodec/svq3.c b/libavcodec/svq3.c
index 8a67836827..fef0202b79 100644
--- a/libavcodec/svq3.c
+++ b/libavcodec/svq3.c
@@ -1439,6 +1439,9 @@ static int svq3_decode_frame(AVCodecContext *avctx, void *data,
     if (svq3_decode_slice_header(avctx))
         return -1;
 
+    if (avpkt->size < s->mb_width * s->mb_height / 8)
+        return AVERROR_INVALIDDATA;
+
     s->pict_type = s->slice_type;
 
     if (s->pict_type != AV_PICTURE_TYPE_B)