diff --git a/libavformat/concat.c b/libavformat/concat.c
index 92efc61185..f15cee2ff4 100644
--- a/libavformat/concat.c
+++ b/libavformat/concat.c
@@ -114,6 +114,12 @@ static av_cold int concat_open(URLContext *h, const char *uri, int flags)
             break;
         }
 
+        if (total_size > INT64_MAX - size) {
+            ffurl_close(uc);
+            err = AVERROR_INVALIDDATA;
+            break;
+        }
+
         /* assembling */
         nodes[i].uc   = uc;
         nodes[i].size = size;
@@ -284,6 +290,12 @@ static av_cold int concatf_open(URLContext *h, const char *uri, int flags)
             break;
         }
 
+        if (total_size > INT64_MAX - size) {
+            ffurl_close(uc);
+            err = AVERROR_INVALIDDATA;
+            break;
+        }
+
         nodes = av_fast_realloc(data->nodes, &nodes_size, sizeof(*nodes) * len);
         if (!nodes) {
             ffurl_close(uc);