diff --git a/libavformat/mov.c b/libavformat/mov.c
index 50234f3b5f..38a70589be 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -7122,7 +7122,7 @@ static int mov_probe(const AVProbeData *p)
         int64_t size;
         int minsize = 8;
         /* ignore invalid offset */
-        if ((offset + 8) > (unsigned int)p->buf_size)
+        if ((offset + 8ULL) > (unsigned int)p->buf_size)
             break;
         size = AV_RB32(p->buf + offset);
         if (size == 1 && offset + 16 <= (unsigned int)p->buf_size) {
@@ -7169,6 +7169,8 @@ static int mov_probe(const AVProbeData *p)
             score  = FFMAX(score, AVPROBE_SCORE_EXTENSION);
             break;
         }
+        if (size > INT64_MAX - offset)
+            break;
         offset += size;
     }
     if (score > AVPROBE_SCORE_MAX - 50 && moov_offset != -1) {