diff --git a/src/nvim/spellfile.c b/src/nvim/spellfile.c
index d241f39975..20f4140a65 100644
--- a/src/nvim/spellfile.c
+++ b/src/nvim/spellfile.c
@@ -699,6 +699,7 @@ slang_T *spell_load_file(char *fname, char *lang, slang_T *old_lp, bool silent)
       break;
 
     case SN_MIDWORD:
+      XFREE_CLEAR(lp->sl_midword);
       lp->sl_midword = read_string(fd, (size_t)len);  // <midword>
       if (lp->sl_midword == NULL) {
         goto endFAIL;
@@ -759,6 +760,7 @@ slang_T *spell_load_file(char *fname, char *lang, slang_T *old_lp, bool silent)
       break;
 
     case SN_SYLLABLE:
+      XFREE_CLEAR(lp->sl_syllable);
       lp->sl_syllable = read_string(fd, (size_t)len);  // <syllable>
       if (lp->sl_syllable == NULL) {
         goto endFAIL;
diff --git a/test/functional/core/spellfile_spec.lua b/test/functional/core/spellfile_spec.lua
index 90531de429..1b4a62ecec 100644
--- a/test/functional/core/spellfile_spec.lua
+++ b/test/functional/core/spellfile_spec.lua
@@ -141,5 +141,34 @@ describe('spellfile', function()
       n.insert('abc')
       eq("Vim(normal):E764: Option 'spellfile' is not set", exc_exec('normal! zg'))
     end)
+
+    it('accepts overwrites on midword and syllable section, errors on memory leak', function()
+      api.nvim_set_option_value('runtimepath', testdir, {})
+      -- stylua: ignore
+
+      -- Set SN_MIDWORD and SN_SYLLABLE twice so the loader overwrites lp->sl_midword. Should
+      -- not leak memory.
+      write_file(testdir .. '/spell/en.ascii.spl',
+                 spellheader
+    --            ┌ Section identifier (#SN_MIDWORD)
+    --            │   ┌ Section flags (#SNF_REQUIRED or zero)
+    --            │   │   ┌ Section length (4 bytes, MSB first)
+              .. '\002\001\000\000\000\003abc'  -- SN_MIDWORD (midword = "abc")
+              .. '\002\001\000\000\000\003def'  -- Overwrites SN_MIDWORD (midword = "def")
+    --            ┌ Section identifier (#SN_SYLLABLE)
+    --            │   ┌ Section flags (#SNF_REQUIRED or zero)
+    --            │   │   ┌ Section length (4 bytes, MSB first)
+              .. '\009\001\000\000\000\003ghi'  -- SN_SYLLABLE (syllable = "ghi")
+              .. '\009\001\000\000\000\003jib'  -- Overwrites SN_SYLLABLE (syllable = "jib")
+              .. '\255'                         -- End of sections marker
+              .. '\000\000\000\000'             -- LWORDTREE len
+              .. '\000\000\000\000'             -- KWORDTREE len
+              .. '\000\000\000\000'             -- PREFIXTREE len
+      )
+
+      api.nvim_set_option_value('spelllang', 'en', {})
+      n.command('set spell') -- Should not error
+      eq(true, api.nvim_get_option_value('spell', {}))
+    end)
   end)
 end)