diff --git a/Lib/configparser.py b/Lib/configparser.py
index 2f45e24..042a5c7 100644
--- a/Lib/configparser.py
+++ b/Lib/configparser.py
@@ -563,7 +563,7 @@ class RawConfigParser(MutableMapping):
     # Regular expressions for parsing section headers and options
     _SECT_TMPL = r"""
         \[                                 # [
-        (?P<header>[^]]+)                  # very permissive!
+        (?P<header>.+)                     # very permissive!
         \]                                 # ]
         """
     _OPT_TMPL = r"""