diff --git a/src/lj_load.c b/src/lj_load.c
index 0aab488407..13783af4b3 100644
--- a/src/lj_load.c
+++ b/src/lj_load.c
@@ -34,11 +34,18 @@ static TValue *cpparser(lua_State *L, lua_CFunction dummy, void *ud)
   UNUSED(dummy);
   cframe_errfunc(L->cframe) = -1;  /* Inherit error function. */
   bc = lj_lex_setup(L, ls);
-  if (ls->mode && !strchr(ls->mode, bc ? 'b' : 't')) {
+  /* Disable loading of Lua bytecode. Untrusted bytecode is unsafe and can
+  ** crash the VM or be used for sandbox escapes; see the LuaJIT FAQ.
+  */
+  if (bc) {
     setstrV(L, L->top++, lj_err_str(L, LJ_ERR_XMODE));
     lj_err_throw(L, LUA_ERRSYNTAX);
   }
-  pt = bc ? lj_bcread(ls) : lj_parse(ls);
+  if (ls->mode && !strchr(ls->mode, 't')) {
+    setstrV(L, L->top++, lj_err_str(L, LJ_ERR_XMODE));
+    lj_err_throw(L, LUA_ERRSYNTAX);
+  }
+  pt = lj_parse(ls);
   fn = lj_func_newL_empty(L, pt, tabref(L->env));
   /* Don't combine above/below into one statement. */
   setfuncV(L, L->top++, fn);