AIKIDO-2026-10788

TL;DR

MutableBuffer growth and related buffer helpers used unchecked usize arithmetic when sizing reservations and zero extensions, so extreme lengths could wrap in optimized builds and undermine capacity accounting before allocation. Iterator helpers such as BitChunks could also mis-handle slice lengths when arithmetic overflowed. The release replaces those paths with checked arithmetic and tighter validation so hostile or accidental huge sizes fail deterministically instead of risking inconsistent buffer state or crashes.