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Fencer Vulns
high 8.8

CVE-2026-68409 json

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

published 2026-08-10 2 mo ago modified 2026-10-30 10 d ago also EUVD-2026-55595

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

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. 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.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.12.114, 6.18.42, 7.1.6, 7.2
  • linux Debian 13 6.12.115-2
  • linux Debian 14 7.1.6-1

debian advisories DEBIAN-CVE-2026-68409

  • linux Ubuntu 26.04 LTS 7.0.0-38.38
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1008.9
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1015.15
  • linux-azure Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-38.38.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1013.13

ubuntu advisories UBUNTU-CVE-2026-68409

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-687.58.1.el9_8
  • rv RHEL 9 5.14.0-687.58.1.el9_8
  • perf RHEL 9 5.14.0-687.58.1.el9_8
  • rtla RHEL 9 5.14.0-687.58.1.el9_8
  • libperf RHEL 9 5.14.0-687.58.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.58.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.58.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.58.1.el9_8

red hat advisories RHSA-2026:83156RHSA-2026:82807RHSA-2026:82806RHSA-2026:65334

  • kernel-rt AlmaLinux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel-rt-core AlmaLinux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel-rt-modules AlmaLinux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel-rt-debug-core AlmaLinux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel-rt-debug-modules-extra AlmaLinux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel AlmaLinux 8 4.18.0-553.173.1.el8_10

almalinux advisories ALSA-2026:82806ALSA-2026:82807ALSA-2026:83156ALSA-2026:65334

  • kernel Rocky Linux 9 5.14.0-687.58.1.el9_8
  • kernel-rt Rocky Linux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel Rocky Linux 8 4.18.0-553.173.1.el8_10
  • kernel Rocky Linux 10 6.12.0-211.53.1.el10_2

rocky linux advisories RLSA-2026:83156RLSA-2026:82806RLSA-2026:82807RLSA-2026:65334

  • kernel Azure Linux 3.0 6.6.161.1-1

azure linux advisories AZL-95042

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-68409 updated cvss 7.1

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

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix available
  • Red Hat Enterprise Linux for NVIDIA 26 kernel
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.58.1.el9_8, perf 5.14.0-687.58.1.el9_8, rtla 5.14.0-687.58.1.el9_8, python3-perf 5.14.0-687.58.1.el9_8, kernel-devel-matched 5.14.0-687.58.1.el9_8, kernel-64k-devel-matched 5.14.0-687.58.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:83156
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.53.1.el10_2, perf 6.12.0-211.53.1.el10_2, rtla 6.12.0-211.53.1.el10_2, python3-perf 6.12.0-211.53.1.el10_2, kernel-devel-matched 6.12.0-211.53.1.el10_2, kernel-64k-devel-matched 6.12.0-211.53.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.173.1.el8_10, kernel 4.18.0-553.173.1.el8_10, bpftool 4.18.0-553.173.1.el8_10, kernel-core 4.18.0-553.173.1.el8_10, kernel-tools 4.18.0-553.173.1.el8_10, python3-perf 4.18.0-553.173.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:82807
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.58.1.el9_8, kernel-64k 5.14.0-687.58.1.el9_8, kernel-core 5.14.0-687.58.1.el9_8, kernel-tools 5.14.0-687.58.1.el9_8, kernel-modules 5.14.0-687.58.1.el9_8, kernel-64k-core 5.14.0-687.58.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:83156
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.53.1.el10_2, kernel-64k 6.12.0-211.53.1.el10_2, kernel-core 6.12.0-211.53.1.el10_2, kernel-tools 6.12.0-211.53.1.el10_2, kernel-modules 6.12.0-211.53.1.el10_2, kernel-64k-core 6.12.0-211.53.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.58.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.58.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.58.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.58.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.58.1.el9_8
    fixed: vendor fix RHSA-2026:83156
show 9 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.53.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.53.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.53.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.53.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.53.1.el10_2
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.173.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.173.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.173.1.el8_10
    fixed: vendor fix RHSA-2026:82807
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-kvm 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-core 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-modules 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-debug-kvm 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-debug-core 4.18.0-553.173.1.rt7.514.el8_10, +4 more
    fixed: vendor fix RHSA-2026:82806
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.58.1.el9_8, kernel-rt-64k 5.14.0-687.58.1.el9_8, kernel-rt-core 5.14.0-687.58.1.el9_8, kernel-rt-modules 5.14.0-687.58.1.el9_8, kernel-rt-64k-core 5.14.0-687.58.1.el9_8, kernel-rt-debug-core 5.14.0-687.58.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:83156
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.53.1.el10_2, kernel-rt-64k 6.12.0-211.53.1.el10_2, kernel-rt-core 6.12.0-211.53.1.el10_2, kernel-rt-modules 6.12.0-211.53.1.el10_2, kernel-rt-64k-core 6.12.0-211.53.1.el10_2, kernel-rt-debug-core 6.12.0-211.53.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.58.1.el9_8, kernel-rt-core 5.14.0-687.58.1.el9_8, kernel-rt-modules 5.14.0-687.58.1.el9_8, kernel-rt-debug-core 5.14.0-687.58.1.el9_8, kernel-rt-modules-core 5.14.0-687.58.1.el9_8, kernel-rt-debug-modules 5.14.0-687.58.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:83156
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.53.1.el10_2, kernel-rt-core 6.12.0-211.53.1.el10_2, kernel-rt-modules 6.12.0-211.53.1.el10_2, kernel-rt-debug-core 6.12.0-211.53.1.el10_2, kernel-rt-modules-core 6.12.0-211.53.1.el10_2, kernel-rt-debug-modules 6.12.0-211.53.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-core 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-modules 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-debug-core 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-debug-modules 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-modules-extra 4.18.0-553.173.1.rt7.514.el8_10, +2 more
    fixed: vendor fix RHSA-2026:82806
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
24 d ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.