Caliptra Core Firmware EUVD-2026-47746

Caliptra is an open-source hardware Root of Trust (RoT) IP core maintained by CHIPSALLIANCE and adopted by hyperscalers and silicon vendors (Google, AMD, Microsoft) for data-center-grade attestation and key management. The Core Runtime Firmware runs on Caliptra's embedded RISC-V core and exposes a mailbox interface through which the host SoC communicates. In subsystem mode, Caliptra acts as a service provider to a higher-level firmware layer; commands routed through the mailbox are expected to be authorized before processing. The three affected command handlers - INVOKE_DPE_MLDSA87 (invoking the DICE Protection Environment with the post-quantum ML-DSA-87/Dilithium signature scheme), CM_AES_GCM_DECRYPT_DMA (AES-GCM decryption via Direct Memory Access), and EXTERNAL_MAILBOX_CMD (a pass-through for external commands) - accept AXI bus addresses from the caller without first verifying authorization. AXI (Advanced eXtensible Interface, part of ARM AMBA) addresses control where DMA operations read or write physical memory; an unverified AXI address can point to regions that crash the firmware or corrupt adjacent state. CWE-862 (Missing Authorization) is the root cause: the firmware performs the requested operation without first confirming the caller is entitled to supply arbitrary AXI targets in subsystem mode.