CVE-2026-19508 [CRITICAL] – Heap-based buffer overflow in the multipart form-data parser in `jst_post.c` in RDK-B WebU

Heap-based buffer overflow in the multipart form-data parser in `jst_post.c` in RDK-B WebUI `rdkb-2025q4-kirkstone.04.10.26` allows a remote unauthenticated attacker to cause memory corruption and denial of service, and potentially execute arbitrary code, via a crafted multipart/form-data request.