Out-of-bounds read in Linux kernel - CVE-2026-52956

Vulnerability identifier: #VU135427

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-52956

CWE-ID: CWE-125

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an out-of-bounds read in __ceph_x_decrypt() when processing a crafted Ceph authentication reply message. A remote attacker can send a specially crafted message frame to cause a denial of service.

The issue can be triggered when the ciphertext is too short to contain a ceph_x_encrypt_header, such as in a FRAME_TAG_AUTH_REPLY_MORE message.

Linux kernel
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Live Patching
SUSE Real Time Module
Basesystem Module
Development Tools Module
Legacy Module
Public Cloud Module
openSUSE Leap
Ubuntu
kernel-livepatch-6_4_0-150600_23_125-default-debuginfo
kernel-livepatch-6_4_0-150600_23_125-default
kernel-livepatch-SLE15-SP6_Update_29-debugsource
kernel-livepatch-6_4_0-150700_7_67-rt-debuginfo
kernel-livepatch-SLE15-SP7-RT_Update_18-debugsource
kernel-livepatch-6_4_0-150700_7_67-rt
kernel-livepatch-SLE15-SP7_Update_19-debugsource
kernel-livepatch-6_4_0-150700_53_73-default-debuginfo
kernel-livepatch-6_4_0-150700_53_73-default
kernel-obs-qa
gfs2-kmp-default-debuginfo
kernel-default-devel-debuginfo
reiserfs-kmp-default-debuginfo
ocfs2-kmp-default
kernel-default-extra
gfs2-kmp-default
cluster-md-kmp-default
dlm-kmp-default-debuginfo
dtb-socionext
kernel-kvmsmall-devel-debuginfo
reiserfs-kmp-default
dlm-kmp-64kb-debuginfo
kernel-default-livepatch
kernel-default-extra-debuginfo
kernel-default-optional-debuginfo
kselftests-kmp-default
kernel-default-devel
kernel-default-debuginfo
dlm-kmp-default
kernel-default-optional
kernel-obs-build-debugsource
kernel-default-debugsource
kernel-obs-build
cluster-md-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
kselftests-kmp-default-debuginfo
kernel-syms
kernel-debug-devel
kernel-default-vdso-debuginfo
kernel-debug-vdso
kernel-default-vdso
kernel-kvmsmall-vdso-debuginfo
kernel-kvmsmall-vdso
kernel-debug-vdso-debuginfo
kernel-zfcpdump-debugsource
kernel-zfcpdump-debuginfo
kernel-debug
kernel-64kb
kernel-docs
dtb-aarch64
kernel-debug-debuginfo
kernel-kvmsmall-devel
kernel-debug-devel-debuginfo
kernel-debug-debugsource
kernel-default
kernel-kvmsmall
kernel-default-livepatch-devel
kernel-zfcpdump
kernel-source
kernel-docs-html
kernel-devel
kernel-macros
kernel-source-vanilla
kernel-kvmsmall-debugsource
kernel-kvmsmall-debuginfo
kernel-64kb-extra-debuginfo
kernel-64kb-debugsource
ocfs2-kmp-64kb-debuginfo
reiserfs-kmp-64kb-debuginfo
ocfs2-kmp-64kb
kernel-64kb-extra
dtb-mediatek
dtb-xilinx
dtb-nvidia
dtb-apm
dtb-lg
dtb-renesas
dtb-sprd
kernel-64kb-debuginfo
dtb-amd
dtb-amlogic
cluster-md-kmp-64kb-debuginfo
dtb-amazon
dlm-kmp-64kb
kselftests-kmp-64kb-debuginfo
kernel-64kb-optional-debuginfo
gfs2-kmp-64kb-debuginfo
gfs2-kmp-64kb
dtb-rockchip
dtb-freescale
reiserfs-kmp-64kb
dtb-cavium
kernel-64kb-devel
dtb-marvell
dtb-apple
dtb-exynos
dtb-allwinner
dtb-hisilicon
cluster-md-kmp-64kb
dtb-qcom
kernel-64kb-optional
kselftests-kmp-64kb
dtb-altera
dtb-broadcom
kernel-64kb-devel-debuginfo
dtb-arm
kernel-default-base
kernel-default-base-rebuild
kernel-rt-devel-debuginfo
ocfs2-kmp-rt
gfs2-kmp-rt
dlm-kmp-rt-debuginfo
kernel-rt-devel
gfs2-kmp-rt-debuginfo
cluster-md-kmp-rt-debuginfo
kernel-syms-rt
ocfs2-kmp-rt-debuginfo
kernel-rt-debugsource
cluster-md-kmp-rt
dlm-kmp-rt
kernel-rt-debuginfo
kernel-devel-rt
kernel-source-rt
kernel-rt
kernel-azure-devel-debuginfo
kernel-azure
kernel-azure-debuginfo
kernel-azure-debugsource
kernel-azure-devel
linux (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-livepatch-6_4_0-150600_23_125-default-debuginfo - update to 1-150600.13.7.1
kernel-livepatch-6_4_0-150600_23_125-default - update to 1-150600.13.7.1
kernel-livepatch-SLE15-SP6_Update_29-debugsource - update to 1-150600.13.7.1
kernel-livepatch-6_4_0-150700_7_67-rt-debuginfo - update to 1-150700.1.5.1
kernel-livepatch-SLE15-SP7-RT_Update_18-debugsource - update to 1-150700.1.5.1
kernel-livepatch-6_4_0-150700_7_67-rt - update to 1-150700.1.5.1
kernel-livepatch-SLE15-SP7_Update_19-debugsource - update to 1-150700.15.3.4
kernel-livepatch-6_4_0-150700_53_73-default-debuginfo - update to 1-150700.15.3.4
kernel-livepatch-6_4_0-150700_53_73-default - update to 1-150700.15.3.4
kernel-obs-qa - update to 6.4.0-150600.23.125.1
gfs2-kmp-default-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-default-devel-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
reiserfs-kmp-default-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
ocfs2-kmp-default - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-default-extra - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
gfs2-kmp-default - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
cluster-md-kmp-default - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
dlm-kmp-default-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
dtb-socionext - update to 6.4.0-150600.23.125.1
kernel-kvmsmall-devel-debuginfo - update to 6.4.0-150600.23.125.1
reiserfs-kmp-default - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
dlm-kmp-64kb-debuginfo - update to 6.4.0-150600.23.125.1
kernel-default-livepatch - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-default-extra-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-default-optional-debuginfo - update to 6.4.0-150600.23.125.1
kselftests-kmp-default - update to 6.4.0-150600.23.125.1
kernel-default-devel - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-default-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
dlm-kmp-default - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-default-optional - update to 6.4.0-150600.23.125.1
kernel-obs-build-debugsource - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-default-debugsource - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-obs-build - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
cluster-md-kmp-default-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
ocfs2-kmp-default-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kselftests-kmp-default-debuginfo - update to 6.4.0-150600.23.125.1
kernel-syms - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.1
kernel-debug-devel - update to 6.4.0-150600.23.125.1
kernel-default-vdso-debuginfo - update to 6.4.0-150600.23.125.1
kernel-debug-vdso - update to 6.4.0-150600.23.125.1
kernel-default-vdso - update to 6.4.0-150600.23.125.1
kernel-kvmsmall-vdso-debuginfo - update to 6.4.0-150600.23.125.1
kernel-kvmsmall-vdso - update to 6.4.0-150600.23.125.1
kernel-debug-vdso-debuginfo - update to 6.4.0-150600.23.125.1
kernel-zfcpdump-debugsource - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-zfcpdump-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-debug - update to 6.4.0-150600.23.125.1
kernel-64kb - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-docs - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.1
dtb-aarch64 - update to 6.4.0-150600.23.125.1
kernel-debug-debuginfo - update to 6.4.0-150600.23.125.1
kernel-kvmsmall-devel - update to 6.4.0-150600.23.125.1
kernel-debug-devel-debuginfo - update to 6.4.0-150600.23.125.1
kernel-debug-debugsource - update to 6.4.0-150600.23.125.1
kernel-default - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-kvmsmall - update to 6.4.0-150600.23.125.1
kernel-default-livepatch-devel - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-zfcpdump - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
kernel-source - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.1
kernel-docs-html - update to 6.4.0-150600.23.125.1
kernel-devel - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.1
kernel-macros - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.1
kernel-source-vanilla - update to 6.4.0-150600.23.125.1
kernel-kvmsmall-debugsource - update to 6.4.0-150600.23.125.1
kernel-kvmsmall-debuginfo - update to 6.4.0-150600.23.125.1
kernel-64kb-extra-debuginfo - update to 6.4.0-150600.23.125.1
kernel-64kb-debugsource - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
ocfs2-kmp-64kb-debuginfo - update to 6.4.0-150600.23.125.1
reiserfs-kmp-64kb-debuginfo - update to 6.4.0-150600.23.125.1
ocfs2-kmp-64kb - update to 6.4.0-150600.23.125.1
kernel-64kb-extra - update to 6.4.0-150600.23.125.1
dtb-mediatek - update to 6.4.0-150600.23.125.1
dtb-xilinx - update to 6.4.0-150600.23.125.1
dtb-nvidia - update to 6.4.0-150600.23.125.1
dtb-apm - update to 6.4.0-150600.23.125.1
dtb-lg - update to 6.4.0-150600.23.125.1
dtb-renesas - update to 6.4.0-150600.23.125.1
dtb-sprd - update to 6.4.0-150600.23.125.1
kernel-64kb-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
dtb-amd - update to 6.4.0-150600.23.125.1
dtb-amlogic - update to 6.4.0-150600.23.125.1
cluster-md-kmp-64kb-debuginfo - update to 6.4.0-150600.23.125.1
dtb-amazon - update to 6.4.0-150600.23.125.1
dlm-kmp-64kb - update to 6.4.0-150600.23.125.1
kselftests-kmp-64kb-debuginfo - update to 6.4.0-150600.23.125.1
kernel-64kb-optional-debuginfo - update to 6.4.0-150600.23.125.1
gfs2-kmp-64kb-debuginfo - update to 6.4.0-150600.23.125.1
gfs2-kmp-64kb - update to 6.4.0-150600.23.125.1
dtb-rockchip - update to 6.4.0-150600.23.125.1
dtb-freescale - update to 6.4.0-150600.23.125.1
reiserfs-kmp-64kb - update to 6.4.0-150600.23.125.1
dtb-cavium - update to 6.4.0-150600.23.125.1
kernel-64kb-devel - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
dtb-marvell - update to 6.4.0-150600.23.125.1
dtb-apple - update to 6.4.0-150600.23.125.1
dtb-exynos - update to 6.4.0-150600.23.125.1
dtb-allwinner - update to 6.4.0-150600.23.125.1
dtb-hisilicon - update to 6.4.0-150600.23.125.1
cluster-md-kmp-64kb - update to 6.4.0-150600.23.125.1
dtb-qcom - update to 6.4.0-150600.23.125.1
kernel-64kb-optional - update to 6.4.0-150600.23.125.1
kselftests-kmp-64kb - update to 6.4.0-150600.23.125.1
dtb-altera - update to 6.4.0-150600.23.125.1
dtb-broadcom - update to 6.4.0-150600.23.125.1
kernel-64kb-devel-debuginfo - addressed in versions 6.4.0-150600.23.125.1, 6.4.0-150700.53.73.2
dtb-arm - update to 6.4.0-150600.23.125.1
kernel-default-base - addressed in versions 6.4.0-150600.23.125.1.150600.12.58.3, 6.4.0-150700.53.73.2.150700.17.41.4
kernel-default-base-rebuild - update to 6.4.0-150600.23.125.1.150600.12.58.3
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.67.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.67.1
gfs2-kmp-rt - update to 6.4.0-150700.7.67.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-rt-devel - update to 6.4.0-150700.7.67.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-syms-rt - update to 6.4.0-150700.7.67.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-rt-debugsource - update to 6.4.0-150700.7.67.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.67.1
dlm-kmp-rt - update to 6.4.0-150700.7.67.1
kernel-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-devel-rt - update to 6.4.0-150700.7.67.1
kernel-source-rt - update to 6.4.0-150700.7.67.1
kernel-rt - update to 6.4.0-150700.7.67.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.73.2
kernel-azure - update to 6.4.0-150700.53.73.2
kernel-azure-debuginfo - update to 6.4.0-150700.53.73.2
kernel-azure-debugsource - update to 6.4.0-150700.53.73.2
kernel-azure-devel - update to 6.4.0-150700.53.73.2
linux (Ubuntu package) - addressed in versions 7.0.0-28.28, 7.0.0-28.28.1, 7.0.0-1003.4, 7.0.0-1008.8
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1009.9
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15

• https://git.kernel.org/stable/c/821365487aa58d06bda65c676ba215d506ba9768
• https://git.kernel.org/stable/c/c7e9b53aebe401970f1b5f5a01b4e021b18e8bb2

• Out-of-bounds read in Linux kernel ceph
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• SUSE update for the Linux Kernel
• SUSE update for the Linux Kernel
• SUSE update for the Linux Kernel
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws