CVE-2026-0672: reject control characters in the Cookie module - add the
_has_control_character() helper and validate in Morsel.setitem,
Morsel.setdefault(), Morsel.set() and BaseCookie.output(). Applied as the
prerequisite for CVE-2026-3644; Python 2.7.5 shipped neither fix.
CVE-2026-3644: reject control characters in Morsel.update(), the unpickling
path (Morsel.setstate) and Morsel.js_output().
CVE-2026-4224: guard conv_content_model() in pyexpat with
Py_EnterRecursiveCall()/Py_LeaveRecursiveCall() to avoid a C stack overflow
when parsing a deeply nested content model in an inline DTD with a registered
ElementDeclHandler.
CVE-2025-13462: skip the old-v7 AREGTYPE -> DIRTYPE normalization in tarfile
when reading a follow-up header (GNU long name/link or PAX extended header),
so crafted multi-block members are no longer misinterpreted.