diff --git a/src/nvim/option.c b/src/nvim/option.c
index 7a7cda2fa0..ba9d1262d4 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -1455,7 +1455,7 @@ int do_set(char *arg, int opt_flags)
       } else {
         char *startarg = arg;             // remember for error message
         const char *errmsg = NULL;
-        char errbuf[80];
+        char errbuf[ERR_BUFLEN];
 
         do_one_set_option(opt_flags, &arg, &did_show, errbuf, sizeof(errbuf), &errmsg);
 
@@ -3845,7 +3845,7 @@ const char *set_option_value(const char *const name, const OptVal value, int opt
 
   int opt_idx = findoption(name);
   if (opt_idx < 0) {
-    snprintf(errbuf, IOSIZE, _(e_unknown_option2), name);
+    snprintf(errbuf, sizeof(errbuf), _(e_unknown_option2), name);
     return errbuf;
   }
 
diff --git a/src/nvim/option_defs.h b/src/nvim/option_defs.h
index b2e8081a08..6d0401f319 100644
--- a/src/nvim/option_defs.h
+++ b/src/nvim/option_defs.h
@@ -66,6 +66,7 @@ typedef struct {
   /// is parameterized, then the "os_errbuf" buffer is used to store the error
   /// message (when it is not NULL).
   char *os_errbuf;
+  /// length of the error buffer
   size_t os_errbuflen;
 
   void *os_win;
diff --git a/src/nvim/option_vars.h b/src/nvim/option_vars.h
index b0e9ff9434..66185940ca 100644
--- a/src/nvim/option_vars.h
+++ b/src/nvim/option_vars.h
@@ -938,6 +938,8 @@ enum {
 // Value for b_p_ul indicating the global value must be used.
 #define NO_LOCAL_UNDOLEVEL (-123456)
 
+#define ERR_BUFLEN 80
+
 #define SB_MAX 100000  // Maximum 'scrollback' value.
 
 #define MAX_NUMBERWIDTH 20      // used for 'numberwidth' and 'statuscolumn'
diff --git a/src/nvim/optionstr.c b/src/nvim/optionstr.c
index 0a7d77e817..544524dd42 100644
--- a/src/nvim/optionstr.c
+++ b/src/nvim/optionstr.c
@@ -442,7 +442,7 @@ int check_signcolumn(win_T *wp)
 const char *check_stl_option(char *s)
 {
   int groupdepth = 0;
-  static char errbuf[80];
+  static char errbuf[ERR_BUFLEN];
 
   while (*s) {
     // Check for valid keys after % sequences
diff --git a/test/functional/legacy/crash_spec.lua b/test/functional/legacy/crash_spec.lua
index 979ebd9e33..094bea253e 100644
--- a/test/functional/legacy/crash_spec.lua
+++ b/test/functional/legacy/crash_spec.lua
@@ -21,3 +21,13 @@ it('no crash when ending Visual mode close the window to switch to', function()
   command('wincmd p')
   assert_alive()
 end)
+
+it('no crash when truncating overlong message', function()
+  pcall(command, 'source test/old/testdir/crash/vim_msg_trunc_poc')
+  assert_alive()
+end)
+
+it('no crash with very long option error message', function()
+  pcall(command, 'source test/old/testdir/crash/poc_did_set_langmap')
+  assert_alive()
+end)
diff --git a/test/functional/legacy/messages_spec.lua b/test/functional/legacy/messages_spec.lua
index e0cc1dc79c..146b00acb0 100644
--- a/test/functional/legacy/messages_spec.lua
+++ b/test/functional/legacy/messages_spec.lua
@@ -801,9 +801,4 @@ describe('messages', function()
     ]])
     os.remove('b.txt')
   end)
-
-  it('no crash when truncating overlong message', function()
-    pcall(command, 'source test/old/testdir/crash/vim_msg_trunc_poc')
-    assert_alive()
-  end)
 end)
diff --git a/test/old/testdir/crash/poc_did_set_langmap b/test/old/testdir/crash/poc_did_set_langmap
new file mode 100644
index 0000000000..f77145b9d1
--- /dev/null
+++ b/test/old/testdir/crash/poc_did_set_langmap
@@ -0,0 +1 @@
+se lmap=°xÿ7sil;drlmap=°xÿ7sil;drmo: pm313"
\ No newline at end of file
diff --git a/test/old/testdir/test_crash.vim b/test/old/testdir/test_crash.vim
index eef1731454..1d4f435e4d 100644
--- a/test/old/testdir/test_crash.vim
+++ b/test/old/testdir/test_crash.vim
@@ -142,6 +142,13 @@ func Test_crash1_2()
     \ '  && echo "crash 3: [OK]" >> '.. result .. "\<cr>")
   call TermWait(buf, 150)
 
+  let file = 'crash/poc_did_set_langmap'
+  let cmn_args = "%s -u NONE -i NONE -n -X -m -n -e -s -S %s -c ':qa!'"
+  let args = printf(cmn_args, vim, file)
+  call term_sendkeys(buf, args ..
+    \ ' ; echo "crash 4: [OK]" >> '.. result .. "\<cr>")
+  call TermWait(buf, 150)
+
   " clean up
   exe buf .. "bw!"
 
@@ -151,6 +158,7 @@ func Test_crash1_2()
       \ 'crash 1: [OK]',
       \ 'crash 2: [OK]',
       \ 'crash 3: [OK]',
+      \ 'crash 4: [OK]',
       \ ]
 
   call assert_equal(expected, getline(1, '$'))