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 c60953b38ee5cee3e986b02f57c49635de5b662f..edf13c6cd435359c5c8f1a1a07e20c67749d74fb 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -4940,6 +4940,16 @@ 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 9038cbb2fa5500c9c8a2ff73bc953c199be22e02..d4498fd8b2e5b86a4229faaadf9c8d0d63e4e17a 100644
--- a/src/box/box.h
+++ b/src/box/box.h
@@ -119,6 +119,12 @@ 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/lua/iproto.c b/src/box/lua/iproto.c
index 610ec9bdd6f16b146d1cbb2a85d042be530aad86..a476ea1f18db8db1d81adca6b064e22ec3882d20 100644
--- a/src/box/lua/iproto.c
+++ b/src/box/lua/iproto.c
@@ -313,6 +313,8 @@ 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 26d18692c98b2da3536488c14c4caa770c72e7a7..0433c1e40ccc5472ef7a9f4256f4a4a87fb58328 100644
--- a/src/box/lua/load_cfg.lua
+++ b/src/box/lua/load_cfg.lua
@@ -979,9 +979,8 @@ 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 fe42aae167895539cc66f7cb2dc1f6973ab82af2..9c53999c3d05afd86af77c746f2bcc8c37977747 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 eebf47233649d395e0146726c9b399e7db97d717..fe4ec24294d6692efa19abfe18303e5b11267eaf 100644
--- a/test/box/error.result
+++ b/test/box/error.result
@@ -931,7 +931,7 @@ e:unpack()
  |   base_type: CustomError
  |   type: TestType
  |   custom_type: TestType
- |   message: 
+ |   message:
  |   trace:
  |   - file: '[string "e = box.error.new({type = ''TestType''}) "]'
  |     line: 1