diff --git a/changelog.d/6074.feature b/changelog.d/6074.feature
new file mode 100644
index 0000000000..b7aa9c99d8
--- /dev/null
+++ b/changelog.d/6074.feature
@@ -0,0 +1 @@
+Prevent password reset's submit_token endpoint from accepting trailing slashes.
\ No newline at end of file
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 1791f4d79b..3c5b23dc80 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -200,7 +200,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
     """Handles 3PID validation token submission"""
 
     PATTERNS = client_patterns(
-        "/password_reset/(?P<medium>[^/]*)/submit_token/*$", releases=(), unstable=True
+        "/password_reset/(?P<medium>[^/]*)/submit_token$", releases=(), unstable=True
     )
 
     def __init__(self, hs):