CVE-2026-12520 Stack buffer overflow and off-by-one writes in Zephyr HL7800 modem AT response handlers

The Sierra Wireless HL7800 cellular modem driver drivers/modem/vendorstandalone/hl7800.c, located at drivers/modem/hl7800.c in v4.4.0 and earlier parses AT responses with roughly twenty handlers that call netbuflinearizevalue, sizeofvalue, buf, 0, len into a 128-byte stack buffer and then write...