Zynq UltraScale+ MPSoC CVE-2026-0461

Exploitation requires the device to be in USB boot mode and an attacker able to drive DFU (Device Firmware Upgrade) download requests over a local/physical USB connection to the affected AMD Zynq UltraScale+ MPSoC/RFSoC or Kria SOM. The specific limiting factors are: (1) physical/local USB access to the device, (2) the device actually being configured or forced into USB boot mode rather than booting from QSPI/eMMC/SD in production, and (3) exploitation occurring during the early boot window before the FSBL hands off. These conditions mean deployed devices that do not expose USB boot in the field are not practically exposed; the attack is most relevant where devices boot via USB or where an attacker controls the physical boot configuration.

This is a genuine integrity-of-boot issue but NOT a widespread remote-exploitation emergency. The CVSS 4.0 vector (AV:L/AC:L/AT:P/PR:N/UI:N) is the key signal: although no privileges or user interaction are needed, the Attack Vector is Local and Attack Requirements are Present (AT:P), meaning the attacker needs the device placed in USB boot mode with a physical/local USB connection - this is not a network-reachable flaw. Vulnerable-system impact is High across confidentiality, integrity and availability (VC:H/VI:H/VA:H), reflecting arbitrary code execution during the trusted boot chain (FSBL), which is severe for a hardware root-of-trust. No EPSS score, no CISA KEV listing, and no public POC are present in the supplied data, so there is no evidence of active or automatable exploitation - consistent with a hardware/firmware bug that requires physical device access rather than a mass-exploitable software defect. Signals are internally consistent: the local vector and physical attack requirement align with the boot-mode description, so there is no CVSS-versus-description conflict to flag. Overall this is a high-severity-but-low-likelihood issue whose realistic risk is concentrated in scenarios where an attacker already has physical or supply-chain access to the device.

An attacker with physical access to an AMD Zynq UltraScale+ device set to USB boot mode connects over USB and issues oversized DFU download requests that overflow the DDR receive buffer into FSBL memory, injecting code that executes within the boot process. No public exploit code was identified in the provided data, so this remains a theoretical/vendor-reported scenario requiring hands-on device access.