CVE-2026-6100: clear dangling next_in pointer on MemoryError in
bz2/lzma decompressors to avoid use-after-free on instance reuse
CVE-2026-4786: validate the post-substitution URL in webbrowser
UnixBrowser.open so that "%action" cannot smuggle a dash-prefixed
flag past the CVE-2026-4519 dash-prefix check