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Fencer Vulns
high 7.5

CVE-2026-23139 json

netfilter: nf_conncount: update last_gc only when GC has been performed

published 2026-02-14 8 mo ago modified 2026-08-05 3 mo ago also EUVD-2026-5898

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

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

netfilter: nf_conncount: update last_gc only when GC has been performed

Currently last_gc is being updated everytime a new connection is tracked, that means that it is updated even if a GC wasn't performed. With a sufficiently high packet rate, it is possible to always bypass the GC, causing the list to grow infinitely.

Update the last_gc value only when a GC has been actually performed.

Patch / fix

  • Linux Linux 6.1.161, 6.6.121, 6.12.66, 6.18.6, 6.19
  • linux Debian 12 6.1.162-1
  • linux Debian 13 6.12.69-1
  • linux Debian 14 6.18.8-1

debian advisories DEBIAN-CVE-2026-23139

  • linux Ubuntu 24.04 LTS 6.8.0-117.117
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1055.58
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1058.61
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1054.60
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1055.56
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1056.62
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1041.44
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1056.60

ubuntu advisories UBUNTU-CVE-2026-23139

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 enterprise linux eus 10.0 6.12.0-55.72.1.el10_0
  • rv enterprise linux eus 10.0 6.12.0-55.72.1.el10_0
  • perf enterprise linux eus 10.0 6.12.0-55.72.1.el10_0
  • rtla enterprise linux eus 10.0 6.12.0-55.72.1.el10_0
  • libperf enterprise linux eus 10.0 6.12.0-55.72.1.el10_0
  • kernel-rt enterprise linux eus 10.0 6.12.0-55.72.1.el10_0
  • kernel-64k enterprise linux eus 10.0 6.12.0-55.72.1.el10_0
  • kernel-core enterprise linux eus 10.0 6.12.0-55.72.1.el10_0

red hat advisories RHSA-2026:15883

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.34.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.34.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.34.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.34.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1.150700.17.23.1

suse advisories SUSE-SU-2026:1081-1SUSE-SU-2026:20873-1SUSE-SU-2026:20838-1SUSE-SU-2026:20931-1SUSE-SU-2026:20845-1SUSE-SU-2026:20876-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.27.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.27.1

opensuse advisories openSUSE-SU-2026:20416-1

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-2026-23139 updated cvss 7.6

kernel: netfilter: nf_conncount: update last_gc only when GC has been performed

  • Red Hat Enterprise Linux 10 kernel
    affected: no fix available
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.72.1.el10_0, perf 6.12.0-55.72.1.el10_0, rtla 6.12.0-55.72.1.el10_0, python3-perf 6.12.0-55.72.1.el10_0, kernel-devel-matched 6.12.0-55.72.1.el10_0, kernel-64k-devel-matched 6.12.0-55.72.1.el10_0, +7 more Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.72.1.el10_0, kernel-64k 6.12.0-55.72.1.el10_0, kernel-core 6.12.0-55.72.1.el10_0, kernel-tools 6.12.0-55.72.1.el10_0, kernel-modules 6.12.0-55.72.1.el10_0, kernel-64k-core 6.12.0-55.72.1.el10_0, +27 more Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.72.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.72.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.72.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.72.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.72.1.el10_0 Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.72.1.el10_0, kernel-rt-64k 6.12.0-55.72.1.el10_0, kernel-rt-core 6.12.0-55.72.1.el10_0, kernel-rt-modules 6.12.0-55.72.1.el10_0, kernel-rt-64k-core 6.12.0-55.72.1.el10_0, kernel-rt-debug-core 6.12.0-55.72.1.el10_0, +14 more Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.72.1.el10_0, kernel-rt-kvm 6.12.0-55.72.1.el10_0, kernel-rt-core 6.12.0-55.72.1.el10_0, kernel-rt-modules 6.12.0-55.72.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.72.1.el10_0, kernel-rt-debug-core 6.12.0-55.72.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:15883
  • 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 Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 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

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

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.