diff --git a/src/nvim/option.c b/src/nvim/option.c
index 3add231e88..40c997ffb7 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -485,6 +485,7 @@ static void change_option_default(const OptIndex opt_idx, OptVal value)
 /// @param  opt_flags  Option flags (can be OPT_LOCAL, OPT_GLOBAL or a combination).
 static void set_option_default(const OptIndex opt_idx, int opt_flags)
 {
+  bool both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
   OptVal def_val = get_option_default(opt_idx, opt_flags);
   set_option_direct(opt_idx, def_val, opt_flags, current_sctx.sc_sid);
 
@@ -495,6 +496,10 @@ static void set_option_default(const OptIndex opt_idx, int opt_flags)
   // The default value is not insecure.
   uint32_t *flagsp = insecure_flag(curwin, opt_idx, opt_flags);
   *flagsp = *flagsp & ~(unsigned)kOptFlagInsecure;
+  if (both) {
+    flagsp = insecure_flag(curwin, opt_idx, OPT_LOCAL);
+    *flagsp = *flagsp & ~(unsigned)kOptFlagInsecure;
+  }
 }
 
 /// Set all options (except terminal options) to their default value.
@@ -3550,15 +3555,22 @@ static const char *did_set_option(OptIndex opt_idx, void *varp, OptVal old_value
   check_redraw(opt->flags);
 
   if (errmsg == NULL) {
-    uint32_t *p = insecure_flag(curwin, opt_idx, opt_flags);
     opt->flags |= kOptFlagWasSet;
 
-    // When an option is set in the sandbox, from a modeline or in secure mode set the kOptFlagInsecure
-    // flag.  Otherwise, if a new value is stored reset the flag.
+    uint32_t *flagsp = insecure_flag(curwin, opt_idx, opt_flags);
+    uint32_t *flagsp_local = scope_both ? insecure_flag(curwin, opt_idx, OPT_LOCAL) : NULL;
+    // When an option is set in the sandbox, from a modeline or in secure mode set the
+    // kOptFlagInsecure flag.  Otherwise, if a new value is stored reset the flag.
     if (!value_checked && (secure || sandbox != 0 || (opt_flags & OPT_MODELINE))) {
-      *p |= kOptFlagInsecure;
+      *flagsp |= kOptFlagInsecure;
+      if (flagsp_local != NULL) {
+        *flagsp_local |= kOptFlagInsecure;
+      }
     } else if (value_replaced) {
-      *p &= ~(unsigned)kOptFlagInsecure;
+      *flagsp &= ~(unsigned)kOptFlagInsecure;
+      if (flagsp_local != NULL) {
+        *flagsp_local &= ~(unsigned)kOptFlagInsecure;
+      }
     }
   }
 
diff --git a/test/old/testdir/test_fold.vim b/test/old/testdir/test_fold.vim
index 6569e032f6..8db66c9be8 100644
--- a/test/old/testdir/test_fold.vim
+++ b/test/old/testdir/test_fold.vim
@@ -1499,7 +1499,7 @@ endfunc
 " in a sandbox
 func Test_foldtext_in_modeline()
   func ModelineFoldText()
-    call feedkeys('aFoo', 'xt')
+    call writefile(['after'], 'Xmodelinefoldtext_write')
     return "folded text"
   endfunc
   let lines =<< trim END
@@ -1510,24 +1510,51 @@ func Test_foldtext_in_modeline()
   END
   call writefile(lines, 'Xmodelinefoldtext', 'D')
 
+  func Check_foldtext_in_modeline(set_cmd)
+    call writefile(['before'], 'Xmodelinefoldtext_write', 'D')
+    split Xmodelinefoldtext
+    call cursor(1, 1)
+    normal! zf3j
+    call assert_equal('folded text', foldtextresult(1))
+    call assert_equal(['before'], readfile('Xmodelinefoldtext_write'))
+
+    setglobal foldtext=ModelineFoldText()
+    call assert_equal('folded text', foldtextresult(1))
+    call assert_equal(['before'], readfile('Xmodelinefoldtext_write'))
+
+    setglobal foldtext&
+    call assert_equal('folded text', foldtextresult(1))
+    call assert_equal(['before'], readfile('Xmodelinefoldtext_write'))
+
+    exe a:set_cmd 'foldtext=ModelineFoldText()'
+    call assert_equal('folded text', foldtextresult(1))
+    call assert_equal(['after'], readfile('Xmodelinefoldtext_write'))
+
+    call writefile(['before'], 'Xmodelinefoldtext_write')
+    exe 'sandbox' a:set_cmd 'foldtext=ModelineFoldText()'
+    call assert_equal('folded text', foldtextresult(1))
+    call assert_equal(['before'], readfile('Xmodelinefoldtext_write'))
+
+    exe a:set_cmd 'foldtext=ModelineFoldText()'
+    call assert_equal('folded text', foldtextresult(1))
+    call assert_equal(['after'], readfile('Xmodelinefoldtext_write'))
+    bw!
+  endfunc
+
   set modeline modelineexpr
-  split Xmodelinefoldtext
+  call Check_foldtext_in_modeline('setlocal')
+  call Check_foldtext_in_modeline('set')
 
-  call cursor(1, 1)
-  normal! zf3j
-  call assert_equal('folded text', foldtextresult(1))
-  call assert_equal(lines, getbufline('', 1, '$'))
-
-  bw!
   set modeline& modelineexpr&
   delfunc ModelineFoldText
+  delfunc Check_foldtext_in_modeline
 endfunc
 
 " Test for setting 'foldexpr' from the modeline and executing the expression
 " in a sandbox
 func Test_foldexpr_in_modeline()
   func ModelineFoldExpr()
-    call feedkeys('aFoo', 'xt')
+    call writefile(['after'], 'Xmodelinefoldexpr_write')
     return strlen(matchstr(getline(v:lnum),'^\s*'))
   endfunc
   let lines =<< trim END
@@ -1541,15 +1568,42 @@ func Test_foldexpr_in_modeline()
   END
   call writefile(lines, 'Xmodelinefoldexpr', 'D')
 
+  func Check_foldexpr_in_modeline(set_cmd)
+    call writefile(['before'], 'Xmodelinefoldexpr_write', 'D')
+    split Xmodelinefoldexpr
+    call assert_equal(2, foldlevel(3))
+    call assert_equal(['before'], readfile('Xmodelinefoldexpr_write'))
+
+    setglobal foldexpr=ModelineFoldExpr()
+    call assert_equal(2, foldlevel(3))
+    call assert_equal(['before'], readfile('Xmodelinefoldexpr_write'))
+
+    setglobal foldexpr&
+    call assert_equal(2, foldlevel(3))
+    call assert_equal(['before'], readfile('Xmodelinefoldexpr_write'))
+
+    exe a:set_cmd 'foldexpr=ModelineFoldExpr()'
+    call assert_equal(2, foldlevel(3))
+    call assert_equal(['after'], readfile('Xmodelinefoldexpr_write'))
+
+    call writefile(['before'], 'Xmodelinefoldexpr_write')
+    exe 'sandbox' a:set_cmd 'foldexpr=ModelineFoldExpr()'
+    call assert_equal(2, foldlevel(3))
+    call assert_equal(['before'], readfile('Xmodelinefoldexpr_write'))
+
+    exe a:set_cmd 'foldexpr=ModelineFoldExpr()'
+    call assert_equal(2, foldlevel(3))
+    call assert_equal(['after'], readfile('Xmodelinefoldexpr_write'))
+    bw!
+  endfunc
+
   set modeline modelineexpr
-  split Xmodelinefoldexpr
+  call Check_foldexpr_in_modeline('setlocal')
+  call Check_foldexpr_in_modeline('set')
 
-  call assert_equal(2, foldlevel(3))
-  call assert_equal(lines, getbufline('', 1, '$'))
-
-  bw!
   set modeline& modelineexpr&
   delfunc ModelineFoldExpr
+  delfunc Check_foldexpr_in_modeline
 endfunc
 
 " Make sure a fold containing a nested fold is split correctly when using
diff --git a/test/old/testdir/test_modeline.vim b/test/old/testdir/test_modeline.vim
index a1050f82cb..6d24e9572d 100644
--- a/test/old/testdir/test_modeline.vim
+++ b/test/old/testdir/test_modeline.vim
@@ -384,8 +384,22 @@ func Test_modeline_nowrap_lcs_extends()
         \ ], 'Xmodeline_nowrap', 'D')
   call NewWindow(10, 20)
 
+  func Check_modeline_nowrap(expect_insecure, expect_secure, set_cmd)
+    edit Xmodeline_nowrap
+    call assert_equal(a:expect_insecure, ScreenLines([1, 5], 20))
+    setglobal nowrap
+    call assert_equal(a:expect_insecure, ScreenLines([1, 5], 20))
+    setglobal wrap
+    call assert_equal(a:expect_insecure, ScreenLines([1, 5], 20))
+    exe a:set_cmd 'nowrap'
+    call assert_equal(a:expect_secure, ScreenLines([1, 5], 20))
+    exe 'sandbox' a:set_cmd 'nowrap'
+    call assert_equal(a:expect_insecure, ScreenLines([1, 5], 20))
+    exe a:set_cmd 'nowrap'
+    call assert_equal(a:expect_secure, ScreenLines([1, 5], 20))
+  endfunc
+
   setlocal nolist listchars=
-  edit Xmodeline_nowrap
   let expect_insecure = [
         \ 'aaa                 ',
         \ 'bbb                 ',
@@ -393,9 +407,6 @@ func Test_modeline_nowrap_lcs_extends()
         \ 'ddd                >',
         \ '~                   ',
         \ ]
-  call assert_equal(expect_insecure, ScreenLines([1, 5], 20))
-
-  setlocal nowrap
   let expect_secure = [
         \ 'aaa                 ',
         \ 'bbb                 ',
@@ -403,7 +414,8 @@ func Test_modeline_nowrap_lcs_extends()
         \ 'ddd                 ',
         \ '~                   ',
         \ ]
-  call assert_equal(expect_secure, ScreenLines([1, 5], 20))
+  call Check_modeline_nowrap(expect_insecure, expect_secure, 'setlocal')
+  call Check_modeline_nowrap(expect_insecure, expect_secure, 'set')
 
   setlocal list listchars=extends:+
   let expect_secure = [
@@ -414,13 +426,45 @@ func Test_modeline_nowrap_lcs_extends()
         \ '~                   ',
         \ ]
   call assert_equal(expect_secure, ScreenLines([1, 5], 20))
+  call Check_modeline_nowrap(expect_insecure, expect_secure, 'setlocal')
+  call Check_modeline_nowrap(expect_insecure, expect_secure, 'set')
 
-  edit Xmodeline_nowrap
-  call assert_equal(expect_insecure, ScreenLines([1, 5], 20))
-  setlocal nowrap
-  call assert_equal(expect_secure, ScreenLines([1, 5], 20))
+  " Other 'listchars' flags are not affected.
+  call writefile([
+        \ "aa\ta",
+        \ "bb\tb",
+        \ "cc\tc              evil",
+        \ "dd\td              vim: nowrap lcs=tab\\:<->",
+        \ ], 'Xmodeline_nowrap')
+  let expect_insecure = [
+        \ 'aa<---->a           ',
+        \ 'bb<---->b           ',
+        \ 'cc<---->c          >',
+        \ 'dd<---->d          >',
+        \ '~                   ',
+        \ ]
+  let expect_secure = [
+        \ 'aa<---->a           ',
+        \ 'bb<---->b           ',
+        \ 'cc<---->c           ',
+        \ 'dd<---->d           ',
+        \ '~                   ',
+        \ ]
+  call Check_modeline_nowrap(expect_insecure, expect_secure, 'setlocal')
+  call Check_modeline_nowrap(expect_insecure, expect_secure, 'set')
+
+  " Same behavior even if modeline sets "extends" to a space.
+  call writefile([
+        \ "aa\ta",
+        \ "bb\tb",
+        \ "cc\tc              evil",
+        \ "dd\td              vim: nowrap lcs=tab\\:<->",
+        \ ], 'Xmodeline_nowrap')
+  call Check_modeline_nowrap(expect_insecure, expect_secure, 'setlocal')
+  call Check_modeline_nowrap(expect_insecure, expect_secure, 'set')
 
   call CloseWindow()
+  delfunc Check_modeline_nowrap
 endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/test/old/testdir/test_statusline.vim b/test/old/testdir/test_statusline.vim
index c9f79dfef7..a92ca42aa0 100644
--- a/test/old/testdir/test_statusline.vim
+++ b/test/old/testdir/test_statusline.vim
@@ -639,4 +639,47 @@ func Test_statusline_highlight_group_cleared()
   call StopVimInTerminal(buf)
 endfunc
 
+" Test for setting both global and local 'statusline' values in a sandbox
+func Test_statusline_in_sandbox()
+  func SandboxStatusLine()
+    call writefile(['after'], 'Xsandboxstatusline_write')
+    return "status line"
+  endfunc
+
+  func Check_statusline_in_sandbox(set_cmd0, set_cmd1)
+    new | only
+    call writefile(['before'], 'Xsandboxstatusline_write', 'D')
+    setlocal statusline=
+    exe 'sandbox' a:set_cmd0 'statusline=%!SandboxStatusLine()'
+    call assert_equal('', &l:statusline)
+    sandbox setlocal statusline=%!SandboxStatusLine()
+    call assert_fails('redrawstatus', 'E48:')
+    call assert_equal(['before'], readfile('Xsandboxstatusline_write'))
+
+    setlocal statusline=%!SandboxStatusLine() | redrawstatus
+    call assert_equal('status line', Screenline(&lines - 1))
+    call assert_equal(['after'], readfile('Xsandboxstatusline_write'))
+
+    call writefile(['before'], 'Xsandboxstatusline_write')
+    setlocal statusline=
+    call assert_fails('redrawstatus', 'E48:')
+    call assert_equal(['before'], readfile('Xsandboxstatusline_write'))
+
+    exe a:set_cmd1 'statusline=%!SandboxStatusLine()' | redrawstatus
+    call assert_equal('', &l:statusline)
+    call assert_equal('status line', Screenline(&lines - 1))
+    call assert_equal(['after'], readfile('Xsandboxstatusline_write'))
+    bw!
+  endfunc
+
+  call Check_statusline_in_sandbox('setglobal', 'setglobal')
+  call Check_statusline_in_sandbox('setglobal', 'set')
+  call Check_statusline_in_sandbox('set', 'setglobal')
+  call Check_statusline_in_sandbox('set', 'set')
+
+  set statusline&
+  delfunc SandboxStatusLine
+  delfunc Check_statusline_in_sandbox
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab