CVE-2026-4395: Heap-based buffer overflow in wc_ecc_import_x963_ex KCAPI path

Heap-based buffer overflow in the KCAPI ECC code path of wceccimportx963ex() in wolfSSL wolfcrypt allows a remote attacker to write attacker-controlled data past the bounds of the pubkeyraw buffer via a crafted oversized EC public key point. The WOLFSSLKCAPIECC code path copies the input to key->pubkeyraw (132 bytes) using XMEMCPY without a bounds check, unlike the ATECC code path which includes a length validation. This can be triggered during TLS key exchange when a malicious peer sends a crafted ECPoint in ServerKeyExchange.