The problem description in #18239 asserted that http://bugs.python.org/issue670664 was fixed in Python 2.6.8, but based on http://bugs.python.org/issue670664#msg146770 it appears that's not correct; the fix was only applied in 2.7, 3.2, and Python trunk. Therefore we must use our patched HTMLParser subclass in all Python 2.6 versions.