PYSEC-2026-3978

libusb before version 1.0.30 contains a NULL pointer dereference vulnerability that allows attackers to crash applications by supplying a malformed USB configuration descriptor where an interface claims bNumEndpoints greater than zero but is followed by a class-specific descriptor whose bLength exceeds the remaining buffer size, causing parse_interface() to return early without allocating the endpoint array. Attackers can exploit this flaw through libusb_get_active_config_descriptor or libusb_get_config_descriptor by providing crafted descriptors via virtualized USB passthrough, file-based descriptor parsing, or network sources, causing any application iterating over endpoints to dereference a NULL endpoint pointer and crash.