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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-06-19 · updated 2026-06-17
Weakness: CWE-824

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.

Affected products

Linux kernel: from 3.19 before 4.19.222; from 4.20 before 5.4.168; from 5.5 before 5.10.88; from 5.11 before 5.15.11; 5.16-rc1, 5.16-rc2, 5.16-rc3, 5.16-rc4, 5.16-rc5 — fixed in 4.19.222, 5.10.88, 5.15.11, 5.4.168

How to fix

Upgrade to a fixed version: Linux kernel 4.19.222, 5.10.88, 5.15.11, 5.4.168. Check the vendor advisory for mitigations.

References

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