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Fencer Vulns
high 7.8

CVE-2026-68338 json

net/packet: avoid fanout hook re-registration after unregister

published 2026-08-10 2 mo ago modified 2026-10-19 20 d ago also EUVD-2026-55439

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

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

net/packet: avoid fanout hook re-registration after unregister

packet_set_ring() temporarily detaches a socket from packet delivery while reconfiguring its ring. It records the previous running state, clears po->num, unregisters the protocol hook when needed, drops po->bind_lock, and later restores po->num and re-registers the hook from the saved was_running value.

That unlocked window can race with NETDEV_UNREGISTER. The notifier can observe the socket as not running, skip __unregister_prot_hook(), and invalidate the per-socket binding by setting po->ifindex to -1 and clearing po->prot_hook.dev. A one-member fanout group can still retain its shared fanout hook device pointer. When packet_set_ring() resumes, re-registering solely from the stale was_running state can re-add the fanout hook after the device has been unregistered.

Treat po->ifindex == -1 as an invalidated binding after reacquiring po->bind_lock. This is distinct from ifindex 0, the normal unbound/wildcard state: ifindex -1 marks an existing device binding that was invalidated when the device was unregistered. Restore po->num as before, but do not re-register the hook if device unregister already detached the socket.

Patch / fix

  • Linux Linux 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2
  • linux Debian 12 6.1.187-1
  • linux Debian 13 6.12.101-1
  • linux Debian 14 7.1.6-1
  • linux-6.12 Debian 12 6.12.101-1~deb12u1

debian advisories DEBIAN-CVE-2026-68338

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 24.04 LTS 6.8.0-147.147
  • linux Ubuntu 26.04 LTS 7.0.0-38.38
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1067.70
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1071.79

ubuntu advisories UBUNTU-CVE-2026-68338

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-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.84.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.84.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1.150700.17.47.1

suse advisories SUSE-SU-2026:4706-1SUSE-SU-2026:4640-1SUSE-SU-2026:24316-1SUSE-SU-2026:24315-1SUSE-SU-2026:24181-1SUSE-SU-2026:24182-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1

  • kernel AlmaLinux 10 6.12.0-211.69.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.69.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.69.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.69.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.69.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.69.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.69.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.69.1.el10_2

almalinux advisories ALSA-2026:91565ALSA-2026:89082ALSA-2026:89083

  • kernel Rocky Linux 10 6.12.0-211.69.1.el10_2
  • kernel-rt Rocky Linux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel Rocky Linux 8 4.18.0-553.178.1.el8_10

rocky linux advisories RLSA-2026:91565RLSA-2026:89082RLSA-2026:89083

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-2026-68338 updated cvss 7.0

kernel: net/packet: avoid fanout hook re-registration after unregister

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: no fix available
  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.69.1.el10_2 Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.69.1.el10_2, perf 6.12.0-211.69.1.el10_2, rtla 6.12.0-211.69.1.el10_2, python3-perf 6.12.0-211.69.1.el10_2, kernel-devel-matched 6.12.0-211.69.1.el10_2, kernel-64k-devel-matched 6.12.0-211.69.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.178.1.el8_10, kernel 4.18.0-553.178.1.el8_10, bpftool 4.18.0-553.178.1.el8_10, kernel-core 4.18.0-553.178.1.el8_10, kernel-tools 4.18.0-553.178.1.el8_10, python3-perf 4.18.0-553.178.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:89083
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.69.1.el10_2, kernel-64k 6.12.0-211.69.1.el10_2, kernel-core 6.12.0-211.69.1.el10_2, kernel-tools 6.12.0-211.69.1.el10_2, kernel-modules 6.12.0-211.69.1.el10_2, kernel-64k-core 6.12.0-211.69.1.el10_2, +28 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.69.1.el10_2
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.178.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.178.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.178.1.el8_10
    fixed: vendor fix RHSA-2026:89083
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.69.1.el10_2
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-kvm 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-core 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-modules 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-kvm 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-core 4.18.0-553.178.1.rt7.519.el8_10, +4 more
    fixed: vendor fix RHSA-2026:89082
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.69.1.el10_2, kernel-rt-64k 6.12.0-211.69.1.el10_2, kernel-rt-core 6.12.0-211.69.1.el10_2, kernel-rt-modules 6.12.0-211.69.1.el10_2, kernel-rt-64k-core 6.12.0-211.69.1.el10_2, kernel-rt-debug-core 6.12.0-211.69.1.el10_2, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.69.1.el10_2, kernel-rt-core 6.12.0-211.69.1.el10_2, kernel-rt-modules 6.12.0-211.69.1.el10_2, kernel-rt-debug-core 6.12.0-211.69.1.el10_2, kernel-rt-modules-core 6.12.0-211.69.1.el10_2, kernel-rt-debug-modules 6.12.0-211.69.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:91565
show 2 more
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-core 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-modules 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-core 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-modules 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-modules-extra 4.18.0-553.178.1.rt7.519.el8_10, +2 more
    fixed: vendor fix RHSA-2026:89082
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    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
23 d ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
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.