diff --git a/src/box/box.cc b/src/box/box.cc
index e8539847f55e6c0fef78f76b93cdabeba6acc54e..a7ab81eda37224024f7620266e2b7c504e93eddf 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -577,24 +577,16 @@ box_check_wal_max_size(int64_t wal_max_size)
 	return wal_max_size;
 }
 
-static int64_t
-box_check_memtx_memory(int64_t memory)
-{
-	if (memory < 0) {
-		tnt_raise(ClientError, ER_CFG, "memtx_memory",
-			  "must not be less than 0");
-	}
-	return memory;
-}
-
-static int64_t
-box_check_vinyl_memory(int64_t memory)
-{
-	if (memory < 0) {
-		tnt_raise(ClientError, ER_CFG, "vinyl_memory",
-			  "must not be less than 0");
-	}
-	return memory;
+static ssize_t
+box_check_memory_quota(const char *quota_name)
+{
+	int64_t size = cfg_geti64(quota_name);
+	if (size >= 0 && (size_t) size <= QUOTA_MAX)
+		return size;
+	diag_set(ClientError, ER_CFG, quota_name,
+		 tt_sprintf("must be >= 0 and <= %zu, but it is %lld",
+		 QUOTA_MAX, size));
+	return -1;
 }
 
 static void
@@ -608,7 +600,8 @@ box_check_vinyl_options(void)
 	double run_size_ratio = cfg_getd("vinyl_run_size_ratio");
 	double bloom_fpr = cfg_getd("vinyl_bloom_fpr");
 
-	box_check_vinyl_memory(cfg_geti64("vinyl_memory"));
+	if (box_check_memory_quota("vinyl_memory") < 0)
+		diag_raise();
 
 	if (read_threads < 1) {
 		tnt_raise(ClientError, ER_CFG, "vinyl_read_threads",
@@ -666,7 +659,8 @@ box_check_config()
 	box_check_checkpoint_count(cfg_geti("checkpoint_count"));
 	box_check_wal_max_size(cfg_geti64("wal_max_size"));
 	box_check_wal_mode(cfg_gets("wal_mode"));
-	box_check_memtx_memory(cfg_geti64("memtx_memory"));
+	if (box_check_memory_quota("memtx_memory") < 0)
+		diag_raise();
 	box_check_memtx_min_tuple_size(cfg_geti64("memtx_min_tuple_size"));
 	box_check_vinyl_options();
 	if (box_check_sql_cache_size(cfg_geti("sql_cache_size")) != 0)
@@ -895,8 +889,10 @@ box_set_memtx_memory(void)
 	struct memtx_engine *memtx;
 	memtx = (struct memtx_engine *)engine_by_name("memtx");
 	assert(memtx != NULL);
-	memtx_engine_set_memory_xc(memtx,
-		box_check_memtx_memory(cfg_geti64("memtx_memory")));
+	ssize_t size = box_check_memory_quota("memtx_memory");
+	if (size < 0)
+		diag_raise();
+	memtx_engine_set_memory_xc(memtx, size);
 }
 
 void
@@ -954,8 +950,10 @@ box_set_vinyl_memory(void)
 {
 	struct engine *vinyl = engine_by_name("vinyl");
 	assert(vinyl != NULL);
-	vinyl_engine_set_memory_xc(vinyl,
-		box_check_vinyl_memory(cfg_geti64("vinyl_memory")));
+	ssize_t size = box_check_memory_quota("vinyl_memory");
+	if (size < 0)
+		diag_raise();
+	vinyl_engine_set_memory_xc(vinyl, size);
 }
 
 void
diff --git a/test/box/cfg.result b/test/box/cfg.result
index 778fb98535874ffdb2c9426fd5786e7087a6d34a..b41d545990ed767d401cfd2c2d88a6311f002fc2 100644
--- a/test/box/cfg.result
+++ b/test/box/cfg.result
@@ -254,11 +254,13 @@ box.cfg{memtx_memory = "100500"}
  | ...
 box.cfg{memtx_memory = -1}
  | ---
- | - error: 'Incorrect value for option ''memtx_memory'': must not be less than 0'
+ | - error: 'Incorrect value for option ''memtx_memory'': must be >= 0 and <= 4398046510080,
+ |     but it is -1'
  | ...
 box.cfg{vinyl_memory = -1}
  | ---
- | - error: 'Incorrect value for option ''vinyl_memory'': must not be less than 0'
+ | - error: 'Incorrect value for option ''vinyl_memory'': must be >= 0 and <= 4398046510080,
+ |     but it is -1'
  | ...
 box.cfg{vinyl = "vinyl"}
  | ---
@@ -268,6 +270,19 @@ box.cfg{vinyl_write_threads = "threads"}
  | ---
  | - error: 'Incorrect value for option ''vinyl_write_threads'': should be of type number'
  | ...
+--
+-- gh-4705: too big memory size led to an assertion.
+--
+box.cfg{memtx_memory = 5000000000000}
+ | ---
+ | - error: 'Incorrect value for option ''memtx_memory'': must be >= 0 and <= 4398046510080,
+ |     but it is 5000000000000'
+ | ...
+box.cfg{vinyl_memory = 5000000000000}
+ | ---
+ | - error: 'Incorrect value for option ''vinyl_memory'': must be >= 0 and <= 4398046510080,
+ |     but it is 5000000000000'
+ | ...
 
 --------------------------------------------------------------------------------
 -- Dynamic configuration check
diff --git a/test/box/cfg.test.lua b/test/box/cfg.test.lua
index b61b0ef24f9a4a5bcb2a41beb3a0d245299ef8d8..56018b1a0e7bb3d5986dcb001598b30b0a924a90 100644
--- a/test/box/cfg.test.lua
+++ b/test/box/cfg.test.lua
@@ -28,6 +28,11 @@ box.cfg{memtx_memory = -1}
 box.cfg{vinyl_memory = -1}
 box.cfg{vinyl = "vinyl"}
 box.cfg{vinyl_write_threads = "threads"}
+--
+-- gh-4705: too big memory size led to an assertion.
+--
+box.cfg{memtx_memory = 5000000000000}
+box.cfg{vinyl_memory = 5000000000000}
 
 --------------------------------------------------------------------------------
 -- Dynamic configuration check