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Unscored CVE-2026-23405 EUVD-2026-17833GHSA-xwx5-hj9g-f35h

apparmor: fix: limit the number of levels of policy namespaces

Published Apr 1, 2026 · Updated May 11, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.17 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.17 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-azure-nvidia-6.14 Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.17 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.17 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-lts-xenial Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.17 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.14 Package: linux-oem-6.17 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.17 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.17 Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.14 Package: linux-riscv-6.17 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

apparmor: fix: limit the number of levels of policy namespaces

Currently the number of policy namespaces is not bounded relying on
the user namespace limit. However policy namespaces aren't strictly
tied to user namespaces and it is possible to create them and nest
them arbitrarily deep which can be used to exhaust system resource.

Hard cap policy namespaces to the same depth as user namespaces.

Affected products

VendorProductAffectedFixed
Linux Linux 2.6.36 5.10.253

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 linux 6.19.6-2 —
Debian 13 linux 6.12.74-2 —
Debian 12 linux 6.1.164-1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1017.21 —
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1087.89 —
Ubuntu 25.10 linux 6.17.0-19.19 —
Ubuntu 25.10 linux-aws +2 6.17.0-1009.9 —
Ubuntu 25.10 linux-azure +1 6.17.0-1010.10 —
Ubuntu 25.10 linux-azure-fde No fix yet —
Ubuntu 25.10 linux-realtime 6.17.0-1008.9 —
Ubuntu 25.10 linux-riscv 6.17.0-19.19.1 —
Ubuntu 24.04 LTS linux 6.8.0-106.106 —
Ubuntu 24.04 LTS linux-aws 6.8.0-1050.53 —
Ubuntu 24.04 LTS linux-aws-6.17 6.17.0-1009.9~24.04.2 —
Ubuntu 24.04 LTS linux-azure 6.8.0-1051.57 —
Ubuntu 24.04 LTS linux-azure-6.17 6.17.0-1010.10~24.04.1 —
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1058.65 —
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1039.42 —
Ubuntu 24.04 LTS linux-gcp 6.8.0-1052.55 —
Ubuntu 24.04 LTS linux-gcp-6.17 6.17.0-1009.9~24.04.3 —
Ubuntu 24.04 LTS linux-gke 6.8.0-1048.53 —
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1035.38 —
Ubuntu 24.04 LTS linux-hwe-6.17 6.17.0-19.19~24.04.2 —
Ubuntu 24.04 LTS linux-ibm 6.8.0-1049.49 —
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-106.106.1 —
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1049.52 —
Ubuntu 24.04 LTS linux-nvidia-6.17 6.17.0-1014.14 —
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1049.52.1 —
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1020.20 —
Ubuntu 24.04 LTS linux-oem-6.17 6.17.0-1017.17 USN-8152-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1047.48 —
Ubuntu 24.04 LTS linux-oracle-6.17 6.17.0-1009.9~24.04.1 —
Ubuntu 24.04 LTS linux-raspi 6.8.0-1050.54 —
Ubuntu 24.04 LTS linux-riscv +18 No fix yet —
Ubuntu 24.04 LTS linux-riscv-6.17 6.17.0-19.19.1~24.04.1 —
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1028.29 USN-8261-1
Ubuntu 22.04 LTS linux +1 5.15.0-173.183 —
Ubuntu 22.04 LTS linux-aws 5.15.0-1103.110 —
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1050.53~22.04.1 —
Ubuntu 22.04 LTS linux-azure 5.15.0-1109.118 USN-8163-2
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1051.57~22.04.1 —
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1109.118.1 —
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1058.65~22.04.1 —
Ubuntu 22.04 LTS linux-gcp 5.15.0-1103.112 —
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1052.55~22.04.1 —
Ubuntu 22.04 LTS linux-gke 5.15.0-1099.105 —
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1086.94 —
Ubuntu 22.04 LTS linux-hwe-6.8 +1 6.8.0-106.106~22.04.1 —
Ubuntu 22.04 LTS linux-ibm +1 5.15.0-1097.100 —
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1049.49~22.04.1 —
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1098.104 —
Ubuntu 22.04 LTS linux-kvm 5.15.0-1095.100 —
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-106.106.1~22.04.1 —
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1098.99 —
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1049.52~22.04.1 —
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1055.55 —
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1044.44 —
Ubuntu 22.04 LTS linux-oracle 5.15.0-1100.106 —
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1047.48~22.04.1 —
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1067.71 —
Show 18 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2040.41 —
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1045.46 —
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.17 6.17.0-1008.9~24.04.1 —
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1096.98 USN-8164-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1102.111 —
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1045.46~22.04.1 —
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1050.53+fips1 —
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1052.58+fips1 USN-8165-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-106.106+fips1 —
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1052.55+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1103.110+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1109.118+fips1 USN-8163-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-173.183+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1103.112+fips1 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-aws-fips 5.4.0-1156.166+fips1 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-azure-fips 5.4.0-1160.166+fips1 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips 5.4.0-1130.140 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-gcp-fips 5.4.0-1159.168+fips1 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-aws-fips 4.15.0-2129.135 USN-8266-1
Ubuntu Pro FIPS-updates 18.04 LTS linux-azure-fips 4.15.0-2109.115 USN-8267-1
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips 4.15.0-1146.158 USN-8266-1
Ubuntu Pro FIPS-updates 18.04 LTS linux-gcp-fips 4.15.0-2092.98 USN-8266-1
Ubuntu Pro FIPS-updates 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux 5.4.0-227.247 —
Ubuntu Pro 20.04 LTS linux-aws 5.4.0-1156.166 —
Ubuntu Pro 20.04 LTS linux-aws-5.15 5.15.0-1103.110~20.04.1 —
Ubuntu Pro 20.04 LTS linux-azure 5.4.0-1160.166 —
Ubuntu Pro 20.04 LTS linux-azure-5.15 5.15.0-1110.119~20.04.1 USN-8243-1
Ubuntu Pro 20.04 LTS linux-bluefield 5.4.0-1116.123 USN-8224-1
Ubuntu Pro 20.04 LTS linux-gcp 5.4.0-1159.168 —
Ubuntu Pro 20.04 LTS linux-gcp-5.15 5.15.0-1103.112~20.04.1 —
Ubuntu Pro 20.04 LTS linux-hwe-5.15 +1 5.15.0-173.183~20.04.1 —
Ubuntu Pro 20.04 LTS linux-ibm 5.4.0-1102.107 —
Ubuntu Pro 20.04 LTS linux-ibm-5.15 5.15.0-1097.100~20.04.1 —
Ubuntu Pro 20.04 LTS linux-intel-iotg-5.15 5.15.0-1098.104~20.04.1 —
Ubuntu Pro 20.04 LTS linux-iot 5.4.0-1060.63 —
Ubuntu Pro 20.04 LTS linux-kvm 5.4.0-1143.152 —
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1055.55~20.04.1 —
Ubuntu Pro 20.04 LTS linux-oracle 5.4.0-1154.164 —
Ubuntu Pro 20.04 LTS linux-oracle-5.15 5.15.0-1100.106~20.04.1 —
Ubuntu Pro 20.04 LTS linux-raspi 5.4.0-1139.152 USN-8098-10
Ubuntu Pro 20.04 LTS linux-riscv-5.15 5.15.0-1098.102~20.04.1 —
Ubuntu Pro 20.04 LTS linux-xilinx-zynqmp 5.4.0-1074.78 —
Ubuntu Pro 18.04 LTS linux 4.15.0-249.261 USN-8266-1
Ubuntu Pro 18.04 LTS linux-aws 4.15.0-1191.204 USN-8266-1
Ubuntu Pro 18.04 LTS linux-aws-5.4 5.4.0-1156.166~18.04.1 —
Ubuntu Pro 18.04 LTS linux-azure-4.15 4.15.0-1200.215 USN-8266-1
Ubuntu Pro 18.04 LTS linux-azure-5.4 5.4.0-1161.167~18.04.1 USN-8201-1
Ubuntu Pro 18.04 LTS linux-gcp-4.15 4.15.0-1184.201 USN-8266-1
Ubuntu Pro 18.04 LTS linux-gcp-5.4 5.4.0-1159.168~18.04.1 —
Ubuntu Pro 18.04 LTS linux-hwe-5.4 5.4.0-227.247~18.04.1 —
Ubuntu Pro 18.04 LTS linux-ibm-5.4 5.4.0-1102.107~18.04.1 —
Ubuntu Pro 18.04 LTS linux-kvm 4.15.0-1173.178 USN-8266-1
Ubuntu Pro 18.04 LTS linux-oracle 4.15.0-1153.164 USN-8266-1
Ubuntu Pro 18.04 LTS linux-oracle-5.4 5.4.0-1154.164~18.04.1 —
Ubuntu Pro 18.04 LTS linux-raspi-5.4 5.4.0-1139.152~18.04.1 USN-8098-10
Ubuntu Pro 16.04 LTS linux +2 No fix yet —
Ubuntu Pro 16.04 LTS linux-aws-hwe 4.15.0-1191.204~16.04.1 USN-8266-1
Ubuntu Pro 16.04 LTS linux-azure 4.15.0-1200.215~16.04.1 USN-8267-1
Ubuntu Pro 16.04 LTS linux-gcp 4.15.0-1184.201~16.04.1 USN-8266-1
Ubuntu Pro 16.04 LTS linux-hwe 4.15.0-249.261~16.04.1 USN-8266-1
Ubuntu Pro 16.04 LTS linux-oracle 4.15.0-1153.164~16.04.1 USN-8267-1
Ubuntu Pro 14.04 LTS linux +2 No fix yet —
Ubuntu Pro 14.04 LTS linux-azure 4.15.0-1200.215~14.04.1 —
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.55.1 SUSE-SU-2026:2238-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.55.1.150700.17.33.1 SUSE-SU-2026:2238-1
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.112.1 SUSE-SU-2026:2195-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.112.1.150600.12.52.1 SUSE-SU-2026:2195-1
Show 4 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 15 SP6 kernel-default-base 6.4.0-150600.23.112.1.150600.12.52.1 SUSE-SU-2026:2195-1
SLES for SAP 15 SP6 kernel-docs +4 6.4.0-150600.23.112.1 SUSE-SU-2026:2195-1
SLE Micro 6.2 kernel-syms +1 6.12.0-160000.33.1 SUSE-SU-2026:21834-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.55.1 SUSE-SU-2026:2238-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_15 1-150700.15.3.1 SUSE-SU-2026:2238-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.112.1 SUSE-SU-2026:2195-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_26 1-150600.13.3.1 SUSE-SU-2026:2195-1

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.130.1-1 —

Advisories 16

References