Vulnerability · Published Aug 10, 2026 · Assigned by Linux

CVE-2026-68166userfaultfd: prevent registration of special VMAs

Unrated

In plain English

A 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 11% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS )–Not rated
Exploit odds (30 days)0.2%top 89.4% 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: userfaultfd: prevent registration of special VMAs Vova Tokarev says: userfaultfd allows registration on shadow stack VMAs. With userfaultfd access, you can register on the shadow stack, discard a page ... and inject a page with chosen return addresses via UFFDIO_COPY. Update vma_can_userfault() to reject VM_SHADOW_STACK. While on it, also reject VM_SPECIAL so that if a driver would implement vm_uffd_ops, it wouldn't be possible to register special VMAs with userfaultfd. Since VM_SPECIAL includes VM_DONTEXPAND which is set but hugetlb, exclude hugetlb VMAs from the check for VM_SPECIAL.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10kernel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-debug6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-debug5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-debug-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-debug-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-debug-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-debug-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-debug-devel-matched6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-debug-devel-matched5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-debug-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-debug-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-debug-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-debug-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-debug-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-debug-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-devel-matched6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-devel-matched5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-64k-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-64k-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-abi-stablelists6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-abi-stablelists5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-cross-headers6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-cross-headers5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-debug6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-debug5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-debug-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-debug-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-debug-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-debug-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-debug-devel-matched6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-debug-devel-matched5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-debug-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-debug-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-debug-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-debug-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-debug-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-debug-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-debug-uki-virt6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-debug-uki-virt5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-devel-matched6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-devel-matched5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-doc6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-doc5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-headers6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-headers5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-modules-extra-matched6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:10kernel-rt6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-debug6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-debug5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-debug-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-debug-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-debug-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-debug-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-debug-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-debug-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-debug-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-debug-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-debug-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-debug-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-64k-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-64k-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-debug6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-debug5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-debug-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-debug-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-debug-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-debug-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-debug-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-debug-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-debug-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-debug-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-debug-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-debug-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-rt-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-rt-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-tools6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-tools5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-tools-libs6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-tools-libs5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-tools-libs-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-tools-libs-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-uki-virt6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-uki-virt5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-uki-virt-addons6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-uki-virt-addons5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-zfcpdump6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-zfcpdump5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-zfcpdump-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-zfcpdump-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-zfcpdump-devel6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-zfcpdump-devel5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-zfcpdump-devel-matched6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-zfcpdump-devel-matched5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-zfcpdump-modules6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-zfcpdump-modules5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-zfcpdump-modules-core6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-zfcpdump-modules-core5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10kernel-zfcpdump-modules-extra6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9kernel-zfcpdump-modules-extra5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10libperf6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9libperf5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10perf6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9perf5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10python3-perf6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9python3-perf5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10rtla6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9rtla5.14.0-687.44.1.el9_8ALSA-2026:63129
AlmaLinux:10rv6.12.0-211.50.1.el10_2ALSA-2026:61887
AlmaLinux:9rv5.14.0-687.44.1.el9_8ALSA-2026:63129
Debian:13linux6.12.105-1DEBIAN-CVE-2026-68166
Debian:14linux7.1.6-1DEBIAN-CVE-2026-68166
Debian:12linux-6.126.12.107-1~deb12u1DEBIAN-CVE-2026-68166
Rocky Linux:10kernel0:6.12.0-211.50.1.el10_2RLSA-2026:61887
Rocky Linux:9kernel0:5.14.0-687.44.1.el9_8RLSA-2026:63129
Ubuntu:24.04:LTSlinuxno fix listedUBUNTU-CVE-2026-68166
Ubuntu:26.04:LTSlinux7.0.0-38.38UBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-68166
Ubuntu:26.04:LTSlinux-aws7.0.0-1014.14UBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-68166
Ubuntu:26.04:LTSlinux-azure7.0.0-1017.17UBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1017.17~24.04.1UBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-68166
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1016.16UBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1016.16~24.04.1UBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-68166
Ubuntu:26.04:LTSlinux-gcp7.0.0-1014.14UBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-68166
Ubuntu:26.04:LTSlinux-gke7.0.0-1008.9UBUNTU-CVE-2026-68166
Ubuntu:24.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-68166
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-68166

Affected products (as reported)

VendorProductVersions
Linux Linux 54007f818206dc27309ca423df4c87dd160a7208 – before d974b4b786214883bd8e56bda10b454c80fd620554007f818206dc27309ca423df4c87dd160a7208 – before 495a28d5a100be1b232633f4c2dcc42ba10b379654007f818206dc27309ca423df4c87dd160a7208 – before 165613191ad9d034bf17c00e3a142f9561597ec554007f818206dc27309ca423df4c87dd160a7208 – before 0c26202b157f1efc3cd2f26f5c30f59b508a6a5d54007f818206dc27309ca423df4c87dd160a7208 – before 3c58f641e813c3c71039f8fd4d4e2a3aab713288
Linux Linux 6.6

References