CVE-2026-44497: Ffi Sighash Callback Stale Buffer None Returncve-2026-44497-ffi-sighash-callback-stale-buffer-none-return
A sighash FFI callback closure returns `None` on hash-type validation failure without overwriting the output buffer with random bytes. When the C/C++ FFI bridge does not treat `None` as a failure signal, the sighash buffer retains a stale digest from a prior computation. An attacker can prime the buffer with a valid digest (via a first script opcode), then t
