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Fencer Vulns
high 7.8

CVE-2026-89488 json

openvswitch: Fix CT limit teardown use-after-free

published 2026-09-11 58 d ago modified 2026-10-19 20 d ago also EUVD-2026-76394

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 2%
public exploits
0
none known

Summary

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

openvswitch: Fix CT limit teardown use-after-free

Packet processing uses CT limit state under RCU, while netns teardown frees that state under ovs_mutex. The CT limit pointer was neither removed from readers nor protected by a grace period, allowing packet processing to dereference the freed state.

An unprivileged user can trigger this bug from a user and network namespace, causing a slab-use-after-free in ovs_ct_execute() when the netns is torn down.

Publish the CT limit pointer through RCU, remove it before teardown, and wait for readers before freeing its contents. Keep ovs_mutex around individual CT limit updates, and use the RCU read-side lock while GET traverses the RCU-protected limit lists.

Netns teardown detaches the RCU-protected CT limit state in the pernet .pre_exit callback while holding ovs_mutex. The pernet core guarantees an RCU grace period between the .pre_exit and .exit callbacks, so the .exit callback completes the teardown without adding any extra synchronization.

The netlink command handlers do not need NULL checks because the userspace netlink socket holds an active reference to its network namespace while a request is processed. The per-netns exit path therefore cannot run concurrently with SET, DEL, or GET for that socket's namespace.

Patch / fix

  • Linux Linux 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.51, 7.2.4, 7.3
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-89488

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-89488

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-source openSUSE Tumbleweed 7.2.7-1.1

opensuse advisories openSUSE-SU-2026:11880-1

  • kernel AlmaLinux 9 5.14.0-687.66.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.66.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.66.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.66.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.66.1.el9_8

almalinux advisories ALSA-2026:95370ALSA-2026:95100ALSA-2026:95212ALSA-2026:95367

  • kernel Rocky Linux 10 6.12.0-211.74.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.66.1.el9_8
  • kernel-rt Rocky Linux 8 4.18.0-553.184.1.rt7.525.el8_10
  • kernel Rocky Linux 8 4.18.0-553.184.1.el8_10

rocky linux advisories RLSA-2026:95367RLSA-2026:95370RLSA-2026:95100RLSA-2026:95212

  • kernel Azure Linux 3.0 6.6.157.1-1

azure linux advisories AZL-100205

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-2026-89488 updated cvss 7.0

kernel: openvswitch: Fix CT limit teardown use-after-free

  • 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 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
    affected: workaround, no fix available
  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.74.1.el10_2
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.66.1.el9_8, perf 5.14.0-687.66.1.el9_8, rtla 5.14.0-687.66.1.el9_8, python3-perf 5.14.0-687.66.1.el9_8, kernel-devel-matched 5.14.0-687.66.1.el9_8, kernel-64k-devel-matched 5.14.0-687.66.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.74.1.el10_2, perf 6.12.0-211.74.1.el10_2, rtla 6.12.0-211.74.1.el10_2, python3-perf 6.12.0-211.74.1.el10_2, kernel-devel-matched 6.12.0-211.74.1.el10_2, kernel-64k-devel-matched 6.12.0-211.74.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.184.1.el8_10, kernel 4.18.0-553.184.1.el8_10, bpftool 4.18.0-553.184.1.el8_10, kernel-core 4.18.0-553.184.1.el8_10, kernel-tools 4.18.0-553.184.1.el8_10, python3-perf 4.18.0-553.184.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:95212
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.66.1.el9_8, kernel-64k 5.14.0-687.66.1.el9_8, kernel-core 5.14.0-687.66.1.el9_8, kernel-tools 5.14.0-687.66.1.el9_8, kernel-modules 5.14.0-687.66.1.el9_8, kernel-64k-core 5.14.0-687.66.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.74.1.el10_2, kernel-64k 6.12.0-211.74.1.el10_2, kernel-core 6.12.0-211.74.1.el10_2, kernel-tools 6.12.0-211.74.1.el10_2, kernel-modules 6.12.0-211.74.1.el10_2, kernel-64k-core 6.12.0-211.74.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.66.1.el9_8
    fixed: vendor fix RHSA-2026:95370
show 10 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.74.1.el10_2
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.184.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.184.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.184.1.el8_10
    fixed: vendor fix RHSA-2026:95212
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.74.1.el10_2
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-kvm 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-core 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-modules 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-debug-kvm 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-debug-core 4.18.0-553.184.1.rt7.525.el8_10, +4 more
    fixed: vendor fix RHSA-2026:95100
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.66.1.el9_8, kernel-rt-64k 5.14.0-687.66.1.el9_8, kernel-rt-core 5.14.0-687.66.1.el9_8, kernel-rt-modules 5.14.0-687.66.1.el9_8, kernel-rt-64k-core 5.14.0-687.66.1.el9_8, kernel-rt-debug-core 5.14.0-687.66.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.74.1.el10_2, kernel-rt-64k 6.12.0-211.74.1.el10_2, kernel-rt-core 6.12.0-211.74.1.el10_2, kernel-rt-modules 6.12.0-211.74.1.el10_2, kernel-rt-64k-core 6.12.0-211.74.1.el10_2, kernel-rt-debug-core 6.12.0-211.74.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.66.1.el9_8, kernel-rt-core 5.14.0-687.66.1.el9_8, kernel-rt-modules 5.14.0-687.66.1.el9_8, kernel-rt-debug-core 5.14.0-687.66.1.el9_8, kernel-rt-modules-core 5.14.0-687.66.1.el9_8, kernel-rt-debug-modules 5.14.0-687.66.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.74.1.el10_2, kernel-rt-core 6.12.0-211.74.1.el10_2, kernel-rt-modules 6.12.0-211.74.1.el10_2, kernel-rt-debug-core 6.12.0-211.74.1.el10_2, kernel-rt-modules-core 6.12.0-211.74.1.el10_2, kernel-rt-debug-modules 6.12.0-211.74.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-core 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-modules 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-debug-core 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-debug-modules 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-modules-extra 4.18.0-553.184.1.rt7.525.el8_10, +2 more
    fixed: vendor fix RHSA-2026:95100
  • 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
    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

0.13% chance of exploitation in the next 30 days, higher than 2% 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

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.