SECURITY UPDATE: configuration injection in configparser via a carriage
return in an attacker-controlled written value
debian/patches/CVE-2026-0864.patch: in Lib/configparser.py, normalize
CR and CRLF to LF before indenting continuation lines in
RawConfigParser._write_section(), so a bare carriage return inside a
written value can no longer round-trip into an unindented line that
the parser reads back as a separate "key = value" pair. Backport of
upstream commit 5858e42c539d (gh-143927 / GH-143929) via the 3.10
backport 12dcbd74d356; applies to 3.7.3 with line offsets only.
Bundles the upstream regression test test_crlf_normalization
(test_configparser.py).