diff --git a/libavformat/shortendec.c b/libavformat/shortendec.c
index a2879dc5a3..f7390b2e62 100644
--- a/libavformat/shortendec.c
+++ b/libavformat/shortendec.c
@@ -40,12 +40,18 @@ static int shn_probe(const AVProbeData *p)
         channels = get_ur_golomb_shorten(&gb, 0);
         blocksize = 256;
     } else {
-        int k;
+        unsigned k;
         k = get_ur_golomb_shorten(&gb, 2);
+        if (k > 31)
+            return 0;
         internal_ftype = get_ur_golomb_shorten(&gb, k);
         k = get_ur_golomb_shorten(&gb, 2);
+        if (k > 31)
+            return 0;
         channels = get_ur_golomb_shorten(&gb, k);
         k = get_ur_golomb_shorten(&gb, 2);
+        if (k > 31)
+            return 0;
         blocksize = get_ur_golomb_shorten(&gb, k);
     }