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Fencer Vulns
high 7.5

CVE-2026-45860 json

netfilter: nf_conncount: increase the connection clean up limit to 64

published 2026-05-27 5 mo ago modified 2026-10-19 20 d ago also EUVD-2026-32326

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 55%
public exploits
0
none known

Summary

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

netfilter: nf_conncount: increase the connection clean up limit to 64

After the optimization to only perform one GC per jiffy, a new problem was introduced. If more than 8 new connections are tracked per jiffy the list won't be cleaned up fast enough possibly reaching the limit wrongly.

In order to prevent this issue, only skip the GC if it was already triggered during the same jiffy and the increment is lower than the clean up limit. In addition, increase the clean up limit to 64 connections to avoid triggering GC too often and do more effective GCs.

This has been tested using a HTTP server and several performance tools while having nft_connlimit/xt_connlimit or OVS limit configured.

Output of slowhttptest + OVS limit at 52000 connections:

slow HTTP test status on 340th second: initializing: 0 pending: 432 connected: 51998 error: 0 closed: 0 service available: YES

Patch / fix

  • Linux Linux 5.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0
  • linux Debian 12 6.1.170-1
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.18.14-1

debian advisories DEBIAN-CVE-2026-45860

  • linux Ubuntu 22.04 LTS 5.15.0-186.196
  • linux Ubuntu 24.04 LTS 6.8.0-134.134
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1112.119
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1060.63
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1112.122
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1063.69
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1108.114
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1058.64

ubuntu advisories UBUNTU-CVE-2026-45860

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-rt Linux Micro 6.2 6.12.0-160000.38.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.38.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1.160000.2.23
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-azure SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.38.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.38.1

suse advisories SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1SUSE-SU-2026:3810-1SUSE-SU-2026:3790-1

  • 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 6.12.0-211.63.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.63.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.63.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.63.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.63.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.63.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.63.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.63.1.el10_2

almalinux advisories ALSA-2026:76738

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-2026-45860 updated cvss 7.5

kernel: netfilter: nf_conncount: increase the connection clean up limit to 64

  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.63.1.el10_2 Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.63.1.el10_2, perf 6.12.0-211.63.1.el10_2, rtla 6.12.0-211.63.1.el10_2, python3-perf 6.12.0-211.63.1.el10_2, kernel-devel-matched 6.12.0-211.63.1.el10_2, kernel-64k-devel-matched 6.12.0-211.63.1.el10_2, +7 more Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.63.1.el10_2, kernel-64k 6.12.0-211.63.1.el10_2, kernel-core 6.12.0-211.63.1.el10_2, kernel-tools 6.12.0-211.63.1.el10_2, kernel-modules 6.12.0-211.63.1.el10_2, kernel-64k-core 6.12.0-211.63.1.el10_2, +28 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.63.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.63.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.63.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.63.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.63.1.el10_2 Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.63.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.63.1.el10_2 Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.63.1.el10_2, kernel-rt-64k 6.12.0-211.63.1.el10_2, kernel-rt-core 6.12.0-211.63.1.el10_2, kernel-rt-modules 6.12.0-211.63.1.el10_2, kernel-rt-64k-core 6.12.0-211.63.1.el10_2, kernel-rt-debug-core 6.12.0-211.63.1.el10_2, +14 more
    +1 more products
    Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.63.1.el10_2, kernel-rt-core 6.12.0-211.63.1.el10_2, kernel-rt-modules 6.12.0-211.63.1.el10_2, kernel-rt-debug-core 6.12.0-211.63.1.el10_2, kernel-rt-modules-core 6.12.0-211.63.1.el10_2, kernel-rt-debug-modules 6.12.0-211.63.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:76738
  • 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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
23 d ago

Exploit prediction

0.74% chance of exploitation in the next 30 days, higher than 55% 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

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
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.