Improper access control in Linux kernel - CVE-2026-64294

Vulnerability identifier: #VU139680

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64294

CWE-ID: CWE-284

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to improper access control in the mincore() and madvise(MADV_PAGEOUT) ownership checks when handling files on idmapped mounts. A local user can access these interfaces on a crafted idmapped mount to disclose sensitive information.

The issue affects side-channel protection logic and occurs because ownership was checked against an idmap that ignored the file's mount idmap.

Linux kernel
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
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
Basesystem Module
Development Tools Module
Legacy Module
Public Cloud Module
SUSE Linux Enterprise Live Patching
Ubuntu
kernel-livepatch-SLE15-SP7_Update_21-debugsource
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo
kernel-livepatch-6_4_0-150700_53_81-default
reiserfs-kmp-default-debuginfo
kernel-zfcpdump-debuginfo
kernel-64kb
kernel-64kb-debuginfo
kernel-64kb-devel
kernel-64kb-devel-debuginfo
kernel-64kb-debugsource
kernel-docs
kernel-syms
kernel-obs-build
kernel-obs-build-debugsource
kernel-source
reiserfs-kmp-default
kernel-zfcpdump-debugsource
kernel-default-livepatch
kernel-default-livepatch-devel
kernel-azure
kernel-azure-devel
kernel-azure-debugsource
kernel-azure-debuginfo
kernel-azure-devel-debuginfo
kernel-default-extra-debuginfo
kernel-default-extra
kernel-zfcpdump
gfs2-kmp-default
cluster-md-kmp-default
kernel-default-debuginfo
ocfs2-kmp-default-debuginfo
dlm-kmp-default-debuginfo
ocfs2-kmp-default
gfs2-kmp-default-debuginfo
dlm-kmp-default
kernel-default-debugsource
kernel-default
kernel-default-devel-debuginfo
kernel-default-devel
kernel-macros
kernel-devel
cluster-md-kmp-default-debuginfo
kernel-default-base
linux (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-livepatch-SLE15-SP7_Update_21-debugsource - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_81-default - update to 1-150700.15.3.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.81.1
kernel-64kb - update to 6.4.0-150700.53.81.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.81.1
kernel-64kb-devel - update to 6.4.0-150700.53.81.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-64kb-debugsource - update to 6.4.0-150700.53.81.1
kernel-docs - update to 6.4.0-150700.53.81.1
kernel-syms - update to 6.4.0-150700.53.81.1
kernel-obs-build - update to 6.4.0-150700.53.81.1
kernel-obs-build-debugsource - update to 6.4.0-150700.53.81.1
kernel-source - update to 6.4.0-150700.53.81.1
reiserfs-kmp-default - update to 6.4.0-150700.53.81.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.81.1
kernel-default-livepatch - update to 6.4.0-150700.53.81.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.81.1
kernel-azure - update to 6.4.0-150700.53.81.1
kernel-azure-devel - update to 6.4.0-150700.53.81.1
kernel-azure-debugsource - update to 6.4.0-150700.53.81.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.81.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-extra - update to 6.4.0-150700.53.81.1
kernel-zfcpdump - update to 6.4.0-150700.53.81.1
gfs2-kmp-default - update to 6.4.0-150700.53.81.1
cluster-md-kmp-default - update to 6.4.0-150700.53.81.1
kernel-default-debuginfo - update to 6.4.0-150700.53.81.1
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
ocfs2-kmp-default - update to 6.4.0-150700.53.81.1
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
dlm-kmp-default - update to 6.4.0-150700.53.81.1
kernel-default-debugsource - update to 6.4.0-150700.53.81.1
kernel-default - update to 6.4.0-150700.53.81.1
kernel-default-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-devel - update to 6.4.0-150700.53.81.1
kernel-macros - update to 6.4.0-150700.53.81.1
kernel-devel - update to 6.4.0-150700.53.81.1
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-base - update to 6.4.0-150700.53.81.1.150700.17.45.1
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13

• https://git.kernel.org/stable/c/04ba248d02d9eaa3d9077b00a6134caa75fa3e90
• https://git.kernel.org/stable/c/5c942ad7df75925ee166e7f0fb36892d8dde376b
• https://git.kernel.org/stable/c/744b23aa430d52f5c8e4dbff7d71496d6643bed2
• https://git.kernel.org/stable/c/8344bdf0629457e532797b42d9d2bbf2a2900bbf
• https://git.kernel.org/stable/c/e187bc02f8fa4226d62814592cf064ee4557c470

• Improper access control in Linux kernel mm
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• SUSE update for the Linux Kernel