diff --git a/src/replication.c b/src/replication.c
index 70ed636957..c0f432559f 100644
--- a/src/replication.c
+++ b/src/replication.c
@@ -3129,7 +3129,7 @@ int replicaTryPartialResynchronization(connection *conn, int read_reply) {
         return PSYNC_TRY_LATER;
     }
 
-    if (!strncmp(reply, "+DUALCONNECTIONSYNC", 15)) {
+    if (!strncmp(reply, "+DUALCONNECTIONSYNC", strlen("+DUALCONNECTIONSYNC")) {
         /* A response of +DUALCONNECTIONSYNC from the primary implies that partial
          * synchronization is not possible and that the primary supports full
          * sync using dedicated RDB connection. Full sync will continue that way. */