diff --git a/changelogs/unreleased/gh-8975-box-iproto-override-without-cfg.md b/changelogs/unreleased/gh-8975-box-iproto-override-without-cfg.md
new file mode 100644
index 0000000000000000000000000000000000000000..0442810ab5a7a3b729dad97bbb5bf9a6fc4825b0
--- /dev/null
+++ b/changelogs/unreleased/gh-8975-box-iproto-override-without-cfg.md
@@ -0,0 +1,4 @@
+## bugfix/box
+
+* Fixed a crash when `box.iproto.override` was called with unconfigured box.
+  Now, an error is raised instead (gh-8975).
diff --git a/src/box/box.cc b/src/box/box.cc
index 2a8c57028f05ebb7a7c296defa6381cc84f20a46..fe1abf8062bc8e96ddcd6f577bedf00b44b39ee3 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -5283,6 +5283,16 @@ box_is_configured(void)
 	return is_box_configured;
 }
 
+int
+box_check_configured(void)
+{
+	if (!is_box_configured) {
+		diag_set(ClientError, ER_UNCONFIGURED);
+		return -1;
+	}
+	return 0;
+}
+
 static void
 box_cfg_xc(void)
 {
diff --git a/src/box/box.h b/src/box/box.h
index 26bc9662549eb3fe32c1531d11c34dd12021eaa5..cc1a8f30a7e2c06f047245c62db61d22263908f9 100644
--- a/src/box/box.h
+++ b/src/box/box.h
@@ -128,6 +128,12 @@ box_cfg(void);
 bool
 box_is_configured(void);
 
+/**
+ * Return 0 if box has been configured, otherwise set diag and return -1.
+ */
+int
+box_check_configured(void);
+
 /** Check if the slice of main cord has expired. */
 int
 box_check_slice_slow(void);
diff --git a/src/box/errcode.h b/src/box/errcode.h
index 115773d3ce459a1b08822f432e1bf5fe93acd6af..4bb2879eb4736939e0f35f15d7e9a8975e607379 100644
--- a/src/box/errcode.h
+++ b/src/box/errcode.h
@@ -326,6 +326,7 @@ struct errcode_record {
 	/*271 */_(ER_SCHEMA_NEEDS_UPGRADE,	"Your schema version is %u.%u.%u while Tarantool %s requires a more recent schema version. Please, consider using box.schema.upgrade().") \
 	/*272 */_(ER_SCHEMA_UPGRADE_IN_PROGRESS, "Schema upgrade is already in progress") \
 	/*273 */_(ER_DEPRECATED,		"%s is deprecated") \
+	/*274 */_(ER_UNCONFIGURED,		"Please call box.cfg{} first") \
 
 /*
  * !IMPORTANT! Please follow instructions at start of the file
diff --git a/src/box/lua/iproto.c b/src/box/lua/iproto.c
index ad4f2515008d62e26b1eb4803328c8a99440cd1a..5fc19ecedd6a2bb0e2b5bdf232af724c72de6f36 100644
--- a/src/box/lua/iproto.c
+++ b/src/box/lua/iproto.c
@@ -309,6 +309,8 @@ lua_req_handler_destroy(void *ctx)
 static int
 lbox_iproto_override(struct lua_State *L)
 {
+	if (box_check_configured() != 0)
+		return luaT_error(L);
 	int n_args = lua_gettop(L);
 	if (n_args != 2)
 		return luaL_error(L, "Usage: "
diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua
index b2be310c1541d9e21d3d38f2dc7fd7358c60a79d..fedf9afb1aee7131f82292d52a9bdb5e6ed31926 100644
--- a/src/box/lua/load_cfg.lua
+++ b/src/box/lua/load_cfg.lua
@@ -1014,9 +1014,8 @@ for k, v in pairs(box) do
 end
 
 setmetatable(box, {
-    __index = function(table, index) -- luacheck: no unused args
-        error(debug.traceback("Please call box.cfg{} first"))
-        error("Please call box.cfg{} first")
+    __index = function()
+        box.error(box.error.UNCONFIGURED)
      end
 })
 
diff --git a/src/box/lua/session.c b/src/box/lua/session.c
index 2777169c45fe48a50241e2734d6389a0c3da9540..811cc958c61bded74cad7b880f9b8f37b156ddd6 100644
--- a/src/box/lua/session.c
+++ b/src/box/lua/session.c
@@ -166,8 +166,8 @@ lbox_session_effective_user(struct lua_State *L)
 static int
 lbox_session_su(struct lua_State *L)
 {
-	if (!box_is_configured())
-		luaL_error(L, "Please call box.cfg{} first");
+	if (box_check_configured() != 0)
+		luaT_error(L);
 	int top = lua_gettop(L);
 	if (top < 1)
 		luaL_error(L, "session.su(): bad arguments");
diff --git a/test/box-luatest/iproto_request_handlers_overriding_test.lua b/test/box-luatest/iproto_request_handlers_overriding_test.lua
index e034b463a7015b1503fda2e5ebaf76446f5f6416..18731e06aa81fc830056152f99ad3516c4ccc7ac 100644
--- a/test/box-luatest/iproto_request_handlers_overriding_test.lua
+++ b/test/box-luatest/iproto_request_handlers_overriding_test.lua
@@ -123,6 +123,14 @@ g.after_all(function(cg)
     cg.server:drop()
 end)
 
+-- Checks that `box.iproto.override` raises an error if called on
+-- an unconfigured instance (gh-8975).
+g.test_box_iproto_override_without_cfg = function()
+    t.assert_error_msg_equals('Please call box.cfg{} first',
+                              box.iproto.override, box.iproto.type.UNKNOWN,
+                              function() end)
+end
+
 -- Checks that `box.iproto.override` errors are handled correctly.
 g.test_box_iproto_override_errors = function(cg)
     cg.server:exec(function()
diff --git a/test/box/error.result b/test/box/error.result
index dac2cf7c742e227a05ddb1b813ec89a3ecb9baa9..3a3c4620211dbe8c141e1bb4baeb38ff27886df3 100644
--- a/test/box/error.result
+++ b/test/box/error.result
@@ -492,6 +492,7 @@ t;
  |   271: box.error.SCHEMA_NEEDS_UPGRADE
  |   272: box.error.SCHEMA_UPGRADE_IN_PROGRESS
  |   273: box.error.DEPRECATED
+ |   274: box.error.UNCONFIGURED
  | ...
 
 test_run:cmd("setopt delimiter ''");