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Vulnerability · Published Apr 1, 2026 · Assigned by Linux

CVE-2026-23403apparmor: fix memory leak in verify_header

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.2%top 92.0% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: apparmor: fix memory leak in verify_header The function sets `*ns = NULL` on every call, leaking the namespace string allocated in previous iterations when multiple profiles are unpacked. This also breaks namespace consistency checking since *ns is always NULL when the comparison is made. Remove the incorrect assignment. The caller (aa_unpack) initializes *ns to NULL once before the loop, which is sufficient.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.164-1DEBIAN-CVE-2026-23403
Debian:13linux6.12.74-2DEBIAN-CVE-2026-23403
Debian:14linux6.19.6-2DEBIAN-CVE-2026-23403
Ubuntu:22.04:LTSlinux5.15.0-173.183UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux6.8.0-106.106UBUNTU-CVE-2026-23403
Ubuntu:25.10linux6.17.0-19.19UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-aws5.15.0-1103.110UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-aws6.8.0-1050.53UBUNTU-CVE-2026-23403
Ubuntu:25.10linux-aws6.17.0-1009.9UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-aws-6.176.17.0-1009.9~24.04.2UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1050.53~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure5.15.0-1109.118UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-azure6.8.0-1051.57UBUNTU-CVE-2026-23403
Ubuntu:25.10linux-azure6.17.0-1010.10UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-azure-6.176.17.0-1010.10~24.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1051.57~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1109.118.1UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1058.65UBUNTU-CVE-2026-23403
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1058.65~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-gcp5.15.0-1103.112UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-gcp6.8.0-1052.55UBUNTU-CVE-2026-23403
Ubuntu:25.10linux-gcp6.17.0-1009.9UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-gcp-6.176.17.0-1009.9~24.04.3UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1052.55~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-gke5.15.0-1099.105UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-gke6.8.0-1048.53UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1086.94UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1035.38UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-hwe-6.176.17.0-19.19~24.04.2UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-ibm5.15.0-1097.100UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-ibm6.8.0-1049.49UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1049.49~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1098.104UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-kvm5.15.0-1095.100UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-173.183UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-106.106.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-106.106.1~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1098.99UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1049.52UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-nvidia-6.176.17.0-1014.14UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1049.52~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1049.52.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1055.55UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1020.20UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1044.44UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-oem-6.176.17.0-1017.17UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-oracle5.15.0-1100.106UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-oracle6.8.0-1047.48UBUNTU-CVE-2026-23403
Ubuntu:25.10linux-oracle6.17.0-1009.9UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-oracle-6.176.17.0-1009.9~24.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1047.48~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-raspi5.15.0-1097.100UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-raspi6.8.0-1050.54UBUNTU-CVE-2026-23403
Ubuntu:25.10linux-raspi6.17.0-1010.10UBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-23403
Ubuntu:25.10linux-realtime6.17.0-1008.9UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-23403
Ubuntu:25.10linux-riscv6.17.0-19.19.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-riscv-6.176.17.0-19.19.1~24.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-23403
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1028.29UBUNTU-CVE-2026-23403
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1067.71UBUNTU-CVE-2026-23403

Affected products (as reported)

VendorProductVersions
Linux Linux dd51c84857630e77c139afe4d9bba65fc051dc3f – before 9d678eb0fe55c9195d9a253e8c5b82a87b930737dd51c84857630e77c139afe4d9bba65fc051dc3f – before 6b79abcb3c985e153fcf9d395e1d4336081aabc2dd51c84857630e77c139afe4d9bba65fc051dc3f – before bcf82c0c5a8b383fd2d5d8f3fd880cdcab2ac557dd51c84857630e77c139afe4d9bba65fc051dc3f – before 663ce34786e759ebcbeb3060685c20bcc886d51add51c84857630e77c139afe4d9bba65fc051dc3f – before 786e2c2a87d9c505f33321d1fd23a176aa8ddeb1dd51c84857630e77c139afe4d9bba65fc051dc3f – before 4f0889f2df1ab99224a5e1ac4e20437eea5fe38edd51c84857630e77c139afe4d9bba65fc051dc3f – before 42fd831abfc15d0643c14688f0522556b347e7e6dd51c84857630e77c139afe4d9bba65fc051dc3f – before e38c55d9f834e5b848bfed0f5c586aaf45acb825
Linux Linux 3.12

References