AMD Zynq™ UltraScale+ MPSoC and RFSoC Devices – Secure Boot Bypass via Unbounded DFU Download Requests
Summary
AMD Zynq™ UltraScale+ MPSoC and RFSoC devices support USB boot mode, a slave boot mechanism that allows a host system to transfer a boot image to the device over USB using the Device Firmware Upgrade (DFU) protocol.
When USB boot mode is included in the FSBL and enabled through mode pins or in the initial boot image, a malicious USB host could send excessive DFU download requests that overflow the DDR receive buffer into FSBL memory, potentially resulting in unauthorized code execution during boot.
This issue does not apply when USB boot mode is not included in the FSBL or is not enabled through mode pins or the initial boot image.
For more information on USB boot mode, see https://docs.amd.com/r/en-US/ug1209-embedded-design-tutorial/Boot-Sequence-for-USB-Boot-Mode.
CVE Details
Refer to Glossary for explanation of terms
| CVE | CVE Description | CVSS Base Score |
| CVE-2026-0461 | Insufficient boundary validation in the USB boot mode implementation of AMD Zynq™ UltraScale+ MPSoC and RFSoC devices could allow unbounded Device Firmware Upgrade (DFU) download requests to overflow the DDR receive buffer into FSBL memory, potentially resulting in unauthorized code execution during the boot process. This issue could impact the confidentiality, integrity, or availability of affected system. | 7.5 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N CWE: 787 - Out-of-bounds Write |
Specific CVSS scores may change subject to your implementation. We encourage you to calculate CVSS scores independently for your system.
Affected Products
AMD recommends implementing the mitigated version indicated below.
*Note: Products believed to not be affected by the listed CVEs are not included.
AMD Adaptive SoCs and FPGAs
| Product | CVE ID | Mitigation | Mitigation Release Date |
| Zynq™ UltraScale+ MPSoCs | CVE-2026-0461 | 2026.1 | 2026-06-23 |
| Zynq™ UltraScale+ RFSoCs | CVE-2026-0461 | 2026.1 | 2026-06-23 |
| Kria SOMs | CVE-2026-0461 | 2026.1 | 2026-06-23 |
Acknowledgement
AMD thanks the following for reporting and engaging in coordinated vulnerability disclosure:
- Internally reported: CVE-2026-0461
Revisions
| Revision Date | Description |
| 2026-09-24 | Initial version |
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