A stack overflow vulnerability was found in libefiboot (part of efivar). The device path node parser does not validate that each node Length field is >= 4 bytes (minimum EFI device path node header size) before recursing. A crafted node with Length < 4 causes infinite recursion in efi_loadopt_is_valid() -> efi_loadopt_optional_data_size(), leading to stack exhaustion and process crash.

Upstream: github.com/rhboot/efivar - no Issues tab or SECURITY.md available. This report serves as initial upstream notification.
Suggested fix: Add minimum length guard: if (dp->length < 4) return -1;