Low-severity (CVSS 3.1 2.5, CWE-754, Debian "unimportant") error-reporting
quirk: 7-Zip 22.01 silently returns OK for an xz file with reserved bits
set in the stream flags instead of flagging it. No memory-safety impact.
NVD's affected-version data is pinned to exactly 22.01 and states "Some
later versions are unaffected"; remediated upstream by version currency,
not by a separate patch, so there is nothing to backport. Verified against
the reporter's PoC (boofish/semantic-bugs pocs/poc2.xz) on this build's
25.01 binaries: the standalone 7za/7zr hard-error (exit 2, "Is not
archive") and 7zz/7z no longer silently accept it (now emit "Warnings: 1"),
so the reported silent-acceptance behavior does not reproduce.