Use After Free in Linux kernel - CVE-2026-23270

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Main Vulnerability Database Vulnerabilities #VU124152

Use After Free in Linux kernel - CVE-2026-23270

Published: March 20, 2026


Vulnerability identifier: #VU124152
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-23270
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a use-after-free condition.

The vulnerability exists due to improper memory management in the act_ct action handling within the net/sched subsystem when processing packets in the egress path. A local user can attach the act_ct action to non-clsact/ingress qdiscs and trigger packet classification that returns TC_ACT_CONSUMED while the socket buffer (skb) is still held by the defragmentation engine, leading to a use-after-free condition.

The vulnerability specifically arises when act_ct is used in contexts not designed to handle TC_ACT_CONSUMED, particularly outside clsact/ingress qdiscs and shared blocks. Exploitation requires the ability to configure traffic control (tc) actions, implying local access and privileges to modify qdisc configurations.


Affected software

Linux kernel
Debian Linux
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for ARM 64
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Anolis OS
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
SUSE Linux Enterprise Live Patching
Public Cloud Module
Legacy Module
Development Tools Module
Basesystem Module
SUSE Real Time Module
Ubuntu
openEuler
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
kernel-livepatch-SLE15-SP7-RT_Update_11-debugsource
kernel-livepatch-6_4_0-150700_7_37-rt
kernel-livepatch-6_4_0-150700_7_37-rt-debuginfo
kernel-livepatch-6_4_0-150700_53_37-default-debuginfo
kernel-livepatch-6_4_0-150700_53_37-default
kernel-livepatch-SLE15-SP7_Update_11-debugsource
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel-debug
kernel-debug-modules
kernel-debug-core
kernel-debug-devel
kernel-doc
kernel-abi-stablelists
python3-perf
perf
kernel-tools-libs-devel
kernel-tools-libs
kernel-tools
kernel-modules-extra
kernel-modules
kernel-headers
kernel-devel
kernel-debug-modules-extra
bpftool
kernel-cross-headers
kernel
kernel-core
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-azure (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux (Debian package)
kernel-syms-rt
kernel-rt-debugsource
kernel-rt
kernel-source-rt
kernel-devel-rt
gfs2-kmp-rt-debuginfo
kernel-rt-debuginfo
gfs2-kmp-rt
cluster-md-kmp-rt
ocfs2-kmp-rt-debuginfo
ocfs2-kmp-rt
kernel-rt-devel
kernel-rt-devel-debuginfo
cluster-md-kmp-rt-debuginfo
dlm-kmp-rt-debuginfo
dlm-kmp-rt
kernel-default-debugsource
kernel-default-devel-debuginfo
kernel-default-devel
kernel-default-debuginfo
kernel-macros
kernel-azure
kernel-default
kernel-64kb-debugsource
kernel-64kb-devel
kernel-64kb-debuginfo
kernel-64kb-devel-debuginfo
kernel-64kb
reiserfs-kmp-default
kernel-zfcpdump-debugsource
kernel-azure-devel-debuginfo
kernel-azure-debuginfo
kernel-azure-debugsource
kernel-azure-devel
ocfs2-kmp-default-debuginfo
gfs2-kmp-default
gfs2-kmp-default-debuginfo
dlm-kmp-default
cluster-md-kmp-default-debuginfo
cluster-md-kmp-default
dlm-kmp-default-debuginfo
ocfs2-kmp-default
kernel-default-extra-debuginfo
kernel-default-extra
kernel-default-livepatch
reiserfs-kmp-default-debuginfo
kernel-source
kernel-syms
kernel-obs-build-debugsource
kernel-default-livepatch-devel
kernel-zfcpdump
kernel-zfcpdump-debuginfo
kernel-docs
kernel-obs-build
kernel-default-base
python3-perf-debuginfo
bpftool-debuginfo
kernel-tools-devel
kernel-tools-debuginfo
kernel-debugsource
kernel-debuginfo
perf-debuginfo
kernel-extra-modules
linux-fips (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-raspi (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-gcp-fips (Ubuntu package)

How to mitigate CVE-2026-23270

Install security update from vendor's repository.

kernel-livepatch-SLE15-SP7-RT_Update_11-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_37-rt - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_37-rt-debuginfo - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_53_37-default-debuginfo - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_37-default - update to 1-150700.15.3.1
kernel-livepatch-SLE15-SP7_Update_11-debugsource - update to 1-150700.15.3.1
kernel (Red Hat package) - addressed in versions 4.18.0-477.150.1.el8_8, 4.18.0-553.126.1.el8_10, 5.14.0-284.174.1.el9_2, 5.14.0-427.127.1.el9_4, 5.14.0-611.54.1.el9_7, 6.12.0-124.55.1.el10_1
kernel-rt (Red Hat package) - addressed in versions 4.18.0-553.126.1.rt7.467.el8_10, 5.14.0-284.174.1.rt14.459.el9_2
kernel-debug - update to 4.18.0-553.126.1.0.1
kernel-debug-modules - update to 4.18.0-553.126.1.0.1
kernel-debug-core - update to 4.18.0-553.126.1.0.1
kernel-debug-devel - update to 4.18.0-553.126.1.0.1
kernel-doc - update to 4.18.0-553.126.1.0.1
kernel-abi-stablelists - update to 4.18.0-553.126.1.0.1
python3-perf - update to 4.18.0-553.126.1.0.1
perf - update to 4.18.0-553.126.1.0.1
kernel-tools-libs-devel - update to 4.18.0-553.126.1.0.1
kernel-tools-libs - update to 4.18.0-553.126.1.0.1
kernel-tools - update to 4.18.0-553.126.1.0.1
kernel-modules-extra - update to 4.18.0-553.126.1.0.1
kernel-modules - update to 4.18.0-553.126.1.0.1
kernel-headers - update to 4.18.0-553.126.1.0.1
kernel-devel - update to 4.18.0-553.126.1.0.1
kernel-debug-modules-extra - update to 4.18.0-553.126.1.0.1
bpftool - update to 4.18.0-553.126.1.0.1
kernel-cross-headers - update to 4.18.0-553.126.1.0.1
kernel - update to 4.18.0-553.126.1.0.1
kernel-core - update to 4.18.0-553.126.1.0.1
linux (Ubuntu package) - addressed in versions 5.15.0.184.155, 5.15.0-184.194, 5.15.0-184.194~20.04.1, 5.15.0.186.166, 5.15.0-186.196, 5.15.0-186.196~20.04.1, 5.15.0.1075.78, 5.15.0-1075.79, 5.15.0.1095.94, 5.15.0-1095.103, 5.15.0.1104.100, 5.15.0-1104.109, 5.15.0.1108.107, 5.15.0-1108.114, 5.15.0.1111.115, 5.15.0-1111.120+fips1, 5.15.0.1112.102, 5.15.0.1112.109, 5.15.0-1112.122, 5.15.0-1112.122+fips1, 6.8.0-136.136, 6.8.0-1046.50, 6.8.0-1059.67, 6.8.0-1064.72, 6.8.0-1064.72~22.04.1, 6.8.1-1056.57, 6.8.1-1056.57~22.04.2
linux-aws (Ubuntu package) - addressed in versions 5.15.0.186.109, 5.15.0-186.196+fips1, 5.15.0.1106.103, 5.15.0-1106.110, 5.15.0.1107.107, 5.15.0-1107.108, 5.15.0.1112.108, 5.15.0.1112.115, 5.15.0-1112.119, 5.15.0-1112.119+fips1, 5.15.0-1112.119~20.04.1, 6.8.0-1061.64+1
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1053.53, 5.15.0.1053.55, 5.15.0.1064.64, 5.15.0-1064.66
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1064.66~20.04.1
linux-intel-iot-realtime (Ubuntu package) - addressed in versions 5.15.0-1104.106, 5.15.0.1104.108, 5.15.0-1107.113~20.04.1
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1106.110~20.04.1
linux-intel-iotg (Ubuntu package) - addressed in versions 5.15.0.1107.106, 5.15.0-1107.113
linux-azure (Ubuntu package) - addressed in versions 5.15.0.1109.105, 5.15.0-1109.115, 5.15.0.1117.115, 5.15.0-1117.126, 6.8.0-1063.71, 6.8.0-1063.71~22.04.1
linux-azure-5.15 (Ubuntu package) - addressed in versions 5.15.0-1109.115~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2
linux-gcp-5.15 (Ubuntu package) - update to 5.15.0-1112.122~20.04.1
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0.1117.102, 5.15.0-1117.126+fips1, 6.8.0-1063.71+fips2
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1117.126, 6.8.0-1062.69
linux (Debian package) - addressed in versions 6.1.170-1, 6.12.85-1
kernel-syms-rt - update to 6.4.0-150700.7.37.1
kernel-rt-debugsource - update to 6.4.0-150700.7.37.2
kernel-rt - update to 6.4.0-150700.7.37.2
kernel-source-rt - update to 6.4.0-150700.7.37.2
kernel-devel-rt - update to 6.4.0-150700.7.37.2
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.37.2
kernel-rt-debuginfo - update to 6.4.0-150700.7.37.2
gfs2-kmp-rt - update to 6.4.0-150700.7.37.2
cluster-md-kmp-rt - update to 6.4.0-150700.7.37.2
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.37.2
ocfs2-kmp-rt - update to 6.4.0-150700.7.37.2
kernel-rt-devel - update to 6.4.0-150700.7.37.2
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.37.2
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.37.2
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.37.2
dlm-kmp-rt - update to 6.4.0-150700.7.37.2
kernel-default-debugsource - update to 6.4.0-150700.53.37.1
kernel-default-devel-debuginfo - update to 6.4.0-150700.53.37.1
kernel-default-devel - update to 6.4.0-150700.53.37.1
kernel-devel - update to 6.4.0-150700.53.37.1
kernel-default-debuginfo - update to 6.4.0-150700.53.37.1
kernel-macros - update to 6.4.0-150700.53.37.1
kernel-azure - update to 6.4.0-150700.53.37.1
kernel-default - update to 6.4.0-150700.53.37.1
kernel-64kb-debugsource - update to 6.4.0-150700.53.37.1
kernel-64kb-devel - update to 6.4.0-150700.53.37.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.37.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.37.1
kernel-64kb - update to 6.4.0-150700.53.37.1
reiserfs-kmp-default - update to 6.4.0-150700.53.37.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.37.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.37.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.37.1
kernel-azure-debugsource - update to 6.4.0-150700.53.37.1
kernel-azure-devel - update to 6.4.0-150700.53.37.1
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.37.1
gfs2-kmp-default - update to 6.4.0-150700.53.37.1
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.37.1
dlm-kmp-default - update to 6.4.0-150700.53.37.1
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.37.1
cluster-md-kmp-default - update to 6.4.0-150700.53.37.1
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.37.1
ocfs2-kmp-default - update to 6.4.0-150700.53.37.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.37.1
kernel-default-extra - update to 6.4.0-150700.53.37.1
kernel-default-livepatch - update to 6.4.0-150700.53.37.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.37.1
kernel-source - update to 6.4.0-150700.53.37.1
kernel-syms - update to 6.4.0-150700.53.37.1
kernel-obs-build-debugsource - update to 6.4.0-150700.53.37.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.37.1
kernel-zfcpdump - update to 6.4.0-150700.53.37.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.37.1
kernel-docs - update to 6.4.0-150700.53.37.1
kernel-obs-build - update to 6.4.0-150700.53.37.1
kernel-default-base - update to 6.4.0-150700.53.37.1.150700.17.25.1
perf - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
python3-perf-debuginfo - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
bpftool-debuginfo - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
bpftool - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-tools-devel - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-tools-debuginfo - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-tools - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-source - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-headers - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-devel - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-debugsource - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-debuginfo - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
python3-perf - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
perf-debuginfo - addressed in versions 6.6.0-145.0.2.130, 6.6.0-145.0.2.142, 6.6.0-145.0.2.143
kernel-extra-modules - update to 6.6.0-145.0.2.143
linux-fips (Ubuntu package) - addressed in versions 6.8.0-136.136+fips2, 6.8.0-136.136.2, 6.8.0-136.136.2~22.04.1, 6.8.0-1058.61
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1030.31, 6.8.0-1033.34, 6.8.0-1061.62, 6.8.0-1061.62~22.04.1
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1058.61~22.04.1
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1059.62, 6.8.0-1059.62.1, 6.8.0-1059.62~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1061.64+fips1, 6.8.0-1061.64~22.04.1
linux-raspi (Ubuntu package) - addressed in versions 6.8.0-1061.65, 6.8.0-2050.52
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1064.72+fips1

External References

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