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Vulnerability · Published May 8, 2026 · Assigned by Linux

CVE-2026-43403nsfs: tighten permission checks for ns iteration ioctls

High 8.8

In plain English

A high-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 0.1% (higher than 3% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.1%top 97.4% 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: nsfs: tighten permission checks for ns iteration ioctls Even privileged services should not necessarily be able to see other privileged service's namespaces so they can't leak information to each other. Use may_see_all_namespaces() helper that centralizes this policy until the nstree adapts.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.85-1DEBIAN-CVE-2026-43403
Debian:14linux6.19.10-1DEBIAN-CVE-2026-43403
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-43403
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-43403
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-43403
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-43403
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-43403
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-43403

Affected products (as reported)

VendorProductVersions
Linux Linux a1d220d9dafa8d76ba60a784a1016c3134e6a1e8 – before 3376b345df155ca36d8611857b41ff7d5183fc38a1d220d9dafa8d76ba60a784a1016c3134e6a1e8 – before 2f3dea284c761c890d676f77d5e55c0c496b4ef4a1d220d9dafa8d76ba60a784a1016c3134e6a1e8 – before 0ad650e60150eda789deca5e78a6a09d26bf8fc9a1d220d9dafa8d76ba60a784a1016c3134e6a1e8 – before e6b899f08066e744f89df16ceb782e06868bd148
Linux Linux 6.12

References