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Response snapshot Oct 30, 2026, 17:36 UTC

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VulnerabilityCVE-2026-68409

Linux kernel: wifi: mac80211: defer link RX stats percpu free to RCU

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: defer link RX stats percpu free to RCU sta_remove_link() frees a removed MLO link's RX stats percpu buffer right away, but defers only the link container to RCU: sta_info_free_link(&alloc->info); kfree_rcu(alloc, rcu_head); The RX fast path reads link_sta under rcu_read_lock and writes the percpu stats.

At a glance

Exploited
Not known
Severity
8.8 High (CVSS 3.1)
Chance of exploitation
0.3% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-68409 (opens a new tab)

What happened

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: defer link RX stats percpu free to RCU

sta_remove_link() frees a removed MLO link's RX stats percpu buffer right away, but defers only the link container to RCU:

sta_info_free_link(&alloc->info); kfree_rcu(alloc, rcu_head);

Continue reading

The RX fast path reads link_sta under rcu_read_lock and writes the percpu stats. A reader that resolved link_sta before the removal keeps the pointer. The container stays alive from the kfree_rcu, so the read still works. But the percpu block it points to is already freed. This needs uses_rss. That is when pcpu_rx_stats exists.

The full STA teardown frees the deflink stats only after synchronize_net(). The link removal path had no such barrier. The race is hard to win in practice, but the free should still wait for RCU.

Free the link together with its data from a single RCU callback, so the percpu block is reclaimed only after readers drain.

Scores and how they were measured

CVSS base severity

8.8

Version 3.1As of

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.3%

Scored Percentile 17.1%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-68409 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  5. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-68409, scored 2026-10-30. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 30). Linux kernel: wifi: mac80211: defer link RX stats percpu free to RCU (CVE-2026-68409). https://kevwire.com/record/CVE-2026-68409

MLA

"Linux kernel: wifi: mac80211: defer link RX stats percpu free to RCU (CVE-2026-68409)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-68409.

Chicago

KEVWire. "Linux kernel: wifi: mac80211: defer link RX stats percpu free to RCU (CVE-2026-68409)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-68409.

Evidence summary (plain text)

Linux kernel: wifi: mac80211: defer link RX stats percpu free to RCU (Aug 10, 2026).
In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: defer link RX stats percpu free to RCU

sta_remove_link() frees a removed MLO link's RX stats percpu buffer right
away, but defers only the link container to RCU:

	sta_info_free_link(&alloc->info);
	kfree_rcu(alloc, rcu_head);

The RX fast path reads link_sta under rcu_read_lock and writes the percpu
stats. A reader that resolved link_sta before the removal keeps the
pointer. The container stays alive from the kfree_rcu, so the read still
works. But the percpu block it points to is already freed.
CVSS 8.8 (version 3.1; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-68409).
EPSS 0.3% for the following 30 days, scored Oct 30, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-68409&date=2026-10-30).
Sources:
NVD CVE-2026-68409: https://nvd.nist.gov/vuln/detail/CVE-2026-68409
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T13:06:45.042Z&lastModEndDate=2026-10-30T14:50:57.069Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T12:22:16.957Z&lastModEndDate=2026-10-30T14:05:57.373Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T11:45:59.009Z&lastModEndDate=2026-10-30T13:20:57.281Z&resultsPerPage=500&startIndex=500
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-68409&date=2026-10-30
Record ID: CVE-2026-68409.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 30, 2026, 14:52 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail