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CVE Record

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

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-47602 is a Linux kernel Wi-Fi stack flaw in mac80211 admission-control handling. The supplied record says non-QoS frames could reach logic that expects a QoS header, causing use of uninitialized data. Business urgency is unclear because no CVSS score, CWE, or exploitation evidence is provided.

Executive priority

Treat this as a targeted kernel maintenance item, not an emergency, unless affected Wi-Fi-enabled Linux devices are business-critical or externally exposed. The absence of severity scoring and exploitation evidence lowers confidence in urgency, but kernel fixes should still enter normal patch cycles.

Technical view

The fix limits admission-control tracking to QoS data frames. Syzbot reported an uninitialized-value condition when a non-QoS nullfunc packet status was processed, because that frame is not long enough to contain the expected QoS header. The affected component is Linux mac80211.

Likely exposure

Exposure is most relevant to Linux systems using affected kernels with the mac80211 wireless networking stack. Wired-only systems or systems without active Wi-Fi functionality are likely less relevant, but the supplied sources do not provide deployment-specific impact boundaries.

Exploitation context

The supplied sources do not state active exploitation, public exploit availability, or KEV listing. The issue was reported by syzbot and resolved through Linux stable kernel commits. Practical exploitability and impact are not established in the provided evidence.

Researcher notes

The record lacks CVSS, CWE, and detailed impact claims. Analysis should stay close to the code-change rationale: admission control must only inspect QoS data frames. Validate exposure by kernel lineage and mac80211 usage, then map to distro backports.

Mitigation direction

  • Update affected Linux kernels to vendor-supported releases containing the referenced mac80211 fix.
  • Prioritize wireless-capable Linux systems and embedded devices using affected kernel branches.
  • Check Linux distribution advisories for backported fixes and exact package versions.
  • Avoid direct wrangler-style source assumptions; rely on vendor kernel package status.

Validation and detection

  • Inventory Linux kernel versions across wireless-capable hosts and appliances.
  • Confirm whether mac80211 is present or used on assessed systems.
  • Compare installed kernel packages against distribution advisories for CVE-2021-47602.
  • Track remediation to the referenced stable kernel commits or vendor backports.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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CVE-2021-47602 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux02219b3abca59fca81711bfe7ee78df7abad97ce, 02219b3abca59fca81711bfe7ee78df7abad97ce, 02219b3abca59fca81711bfe7ee78df7abad97ce, 02219b3abca59fca81711bfe7ee78df7abad97ce, 02219b3abca59fca81711bfe7ee78df7abad97ceunaffected
LinuxLinux3.19, 0, 4.19.222, 5.4.168, 5.10.88, 5.15.11, 5.16affected
Weakness

CWE details

No CWE listed

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