1 files changed, 5 insertions, 3 deletions
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 1d1ddc2245..8619fbb982 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -1122,20 +1122,22 @@ class AuthHandler(BaseHandler):
             Whether self.hash(password) == stored_hash.
         """
 
-        def _do_validate_hash():
+        def _do_validate_hash(checked_hash: bytes):
             # Normalise the Unicode in the password
             pw = unicodedata.normalize("NFKC", password)
 
             return bcrypt.checkpw(
                 pw.encode("utf8") + self.hs.config.password_pepper.encode("utf8"),
-                stored_hash,
+                checked_hash,
             )
 
         if stored_hash:
             if not isinstance(stored_hash, bytes):
                 stored_hash = stored_hash.encode("ascii")
 
-            return await defer_to_thread(self.hs.get_reactor(), _do_validate_hash)
+            return await defer_to_thread(
+                self.hs.get_reactor(), _do_validate_hash, stored_hash
+            )
         else:
             return False