CVE-2026-22693 Null Pointer Dereference in SubtableUnicodesCache::create leading to DoS

HarfBuzz is a text shaping engine. Prior to version 12.3.0, a null pointer dereference vulnerability exists in the SubtableUnicodesCache::create function located in src/hb-ot-cmap-table.hh. The function fails to check if hbmalloc returns NULL before using placement new to construct an object at t...