Use-after-free in Linux kernel - CVE-2021-47639

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Main Vulnerability Database Vulnerabilities #VU104501

Use-after-free in Linux kernel - CVE-2021-47639

Published: February 26, 2025 / Updated: May 11, 2025


Vulnerability identifier: #VU104501
CSH Severity: Low
CVSS v4 BT: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]
CVE-ID: CVE-2021-47639
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the kvm_tdp_mmu_put_root(), tdp_mmu_next_root(), kvm_tdp_mmu_wrprot_slot(), kvm_tdp_mmu_clear_dirty_slot() and kvm_tdp_mmu_zap_collapsible_sptes() functions in arch/x86/kvm/mmu/tdp_mmu.c. A local user can escalate privileges on the system.


Affected software

Linux kernel
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Manager Server
SUSE Manager Retail Branch Server
SUSE Manager Proxy
SUSE Linux Enterprise Micro
SUSE Linux Enterprise Micro for Rancher
SUSE Linux Enterprise Live Patching
openSUSE Leap
openEuler
kernel-livepatch-5_14_21-150400_24_158-default-debuginfo
kernel-livepatch-5_14_21-150400_24_158-default
kernel-livepatch-SLE15-SP4_Update_38-debugsource
kernel-livepatch-5_14_21-150500_55_100-default
kernel-livepatch-5_14_21-150500_55_100-default-debuginfo
kernel-livepatch-SLE15-SP5_Update_25-debugsource
perf-debuginfo
kernel
python3-perf-debuginfo
python3-perf
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
kernel-rt-debugsource
kernel-source-rt
kernel-rt-debuginfo
kernel-rt
reiserfs-kmp-64kb
dtb-mediatek
dtb-arm
kernel-64kb-debugsource
dlm-kmp-64kb
kselftests-kmp-64kb
dtb-marvell
dtb-nvidia
ocfs2-kmp-64kb-debuginfo
dtb-cavium
kernel-64kb-devel
reiserfs-kmp-64kb-debuginfo
kernel-64kb-optional
gfs2-kmp-64kb
kernel-64kb-extra-debuginfo
dtb-rockchip
dtb-apple
dtb-apm
dlm-kmp-64kb-debuginfo
dtb-lg
dtb-amd
kernel-64kb
dtb-amazon
dtb-amlogic
dtb-hisilicon
kernel-64kb-debuginfo
dtb-freescale
dtb-allwinner
cluster-md-kmp-64kb
cluster-md-kmp-64kb-debuginfo
dtb-socionext
ocfs2-kmp-64kb
dtb-renesas
kernel-64kb-optional-debuginfo
dtb-altera
kernel-64kb-devel-debuginfo
dtb-sprd
dtb-xilinx
dtb-exynos
dtb-qcom
dtb-broadcom
kselftests-kmp-64kb-debuginfo
gfs2-kmp-64kb-debuginfo
kernel-docs
kernel-kvmsmall-debugsource
kernel-kvmsmall-debuginfo
kernel-kvmsmall-devel-debuginfo
kernel-default
kernel-kvmsmall-devel
kernel-debug-devel
kernel-debug-debuginfo
kernel-debug-devel-debuginfo
kernel-debug-debugsource
kernel-debug
kernel-docs-html
kernel-source-vanilla
kernel-default-optional
kernel-zfcpdump-debuginfo
kernel-zfcpdump-debugsource
kernel-zfcpdump
kernel-macros
kernel-syms
kernel-default-debugsource
kernel-default-devel
kernel-default-debuginfo
kernel-default-devel-debuginfo
kselftests-kmp-default
kernel-64kb-extra
dtb-aarch64
kernel-kvmsmall
kernel-default-livepatch-devel
cluster-md-kmp-default
kernel-obs-build-debugsource
kernel-default-extra
kernel-default-livepatch
dlm-kmp-default
reiserfs-kmp-default-debuginfo
gfs2-kmp-default
reiserfs-kmp-default
kernel-obs-qa
cluster-md-kmp-default-debuginfo
kernel-default-extra-debuginfo
kselftests-kmp-default-debuginfo
gfs2-kmp-default-debuginfo
dlm-kmp-default-debuginfo
kernel-obs-build
kernel-default-optional-debuginfo
ocfs2-kmp-default
ocfs2-kmp-default-debuginfo
kernel-default-base-rebuild
kernel-default-base
kernel-rt-devel
kernel-rt_debug-devel
dlm-kmp-rt
reiserfs-kmp-rt
kernel-rt_debug-devel-debuginfo
reiserfs-kmp-rt-debuginfo
kernel-rt-vdso-debuginfo
kernel-rt-extra
gfs2-kmp-rt
kernel-rt-livepatch
kernel-rt-vdso
kernel-rt_debug
ocfs2-kmp-rt
kernel-devel-rt
kernel-rt-optional-debuginfo
kernel-syms-rt
kernel-rt_debug-debugsource
ocfs2-kmp-rt-debuginfo
kernel-rt-devel-debuginfo
kernel-rt_debug-vdso
kernel-rt-livepatch-devel
kernel-rt-optional
cluster-md-kmp-rt-debuginfo
gfs2-kmp-rt-debuginfo
kernel-rt_debug-debuginfo
kselftests-kmp-rt-debuginfo
kernel-rt-extra-debuginfo
dlm-kmp-rt-debuginfo
kernel-rt_debug-vdso-debuginfo
kselftests-kmp-rt
cluster-md-kmp-rt
kernel-debug-vdso
kernel-default-vdso
kernel-kvmsmall-vdso-debuginfo
kernel-kvmsmall-vdso
kernel-default-vdso-debuginfo
kernel-debug-vdso-debuginfo

How to mitigate CVE-2021-47639

Install update from vendor's website.

Linux kernel - addressed in versions 5.15.33, 5.16.19, 5.17.2, 5.18
kernel-livepatch-5_14_21-150400_24_158-default-debuginfo - update to 1-150400.9.3.1
kernel-livepatch-5_14_21-150400_24_158-default - update to 1-150400.9.3.1
kernel-livepatch-SLE15-SP4_Update_38-debugsource - update to 1-150400.9.3.1
kernel-livepatch-5_14_21-150500_55_100-default - update to 1-150500.11.3.1
kernel-livepatch-5_14_21-150500_55_100-default-debuginfo - update to 1-150500.11.3.1
kernel-livepatch-SLE15-SP5_Update_25-debugsource - update to 1-150500.11.3.1
perf-debuginfo - update to 5.10.0-254.0.0.157
kernel - update to 5.10.0-254.0.0.157
python3-perf-debuginfo - update to 5.10.0-254.0.0.157
python3-perf - update to 5.10.0-254.0.0.157
perf - update to 5.10.0-254.0.0.157
kernel-tools-devel - update to 5.10.0-254.0.0.157
kernel-tools-debuginfo - update to 5.10.0-254.0.0.157
kernel-tools - update to 5.10.0-254.0.0.157
kernel-source - update to 5.10.0-254.0.0.157
kernel-headers - update to 5.10.0-254.0.0.157
kernel-devel - update to 5.10.0-254.0.0.157
kernel-debugsource - update to 5.10.0-254.0.0.157
kernel-debuginfo - update to 5.10.0-254.0.0.157
kernel-rt-debugsource - addressed in versions 5.14.21-150400.15.115.1, 5.14.21-150500.13.91.1
kernel-source-rt - addressed in versions 5.14.21-150400.15.115.1, 5.14.21-150500.13.91.1
kernel-rt-debuginfo - addressed in versions 5.14.21-150400.15.115.1, 5.14.21-150500.13.91.1
kernel-rt - addressed in versions 5.14.21-150400.15.115.1, 5.14.21-150500.13.91.1
reiserfs-kmp-64kb - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-mediatek - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-arm - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb-debugsource - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dlm-kmp-64kb - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kselftests-kmp-64kb - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-marvell - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-nvidia - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
ocfs2-kmp-64kb-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-cavium - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb-devel - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
reiserfs-kmp-64kb-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb-optional - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
gfs2-kmp-64kb - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb-extra-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-rockchip - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-apple - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-apm - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dlm-kmp-64kb-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-lg - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-amd - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-amazon - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-amlogic - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-hisilicon - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-freescale - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-allwinner - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
cluster-md-kmp-64kb - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
cluster-md-kmp-64kb-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-socionext - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
ocfs2-kmp-64kb - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-renesas - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb-optional-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-altera - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb-devel-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-sprd - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-xilinx - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-exynos - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-qcom - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-broadcom - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kselftests-kmp-64kb-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
gfs2-kmp-64kb-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-docs - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-kvmsmall-debugsource - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-kvmsmall-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-kvmsmall-devel-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-kvmsmall-devel - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-debug-devel - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-debug-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-debug-devel-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-debug-debugsource - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-debug - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-docs-html - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-source-vanilla - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-optional - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-zfcpdump-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-zfcpdump-debugsource - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-zfcpdump - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-source - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-macros - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-devel - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-syms - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-debugsource - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-devel - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-devel-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kselftests-kmp-default - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-64kb-extra - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dtb-aarch64 - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-kvmsmall - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-livepatch-devel - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
cluster-md-kmp-default - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-obs-build-debugsource - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-extra - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-livepatch - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dlm-kmp-default - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
reiserfs-kmp-default-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
gfs2-kmp-default - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
reiserfs-kmp-default - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-obs-qa - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
cluster-md-kmp-default-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-extra-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kselftests-kmp-default-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
gfs2-kmp-default-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
dlm-kmp-default-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-obs-build - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-optional-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
ocfs2-kmp-default - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
ocfs2-kmp-default-debuginfo - addressed in versions 5.14.21-150400.24.158.1, 5.14.21-150500.55.100.1
kernel-default-base-rebuild - addressed in versions 5.14.21-150400.24.158.1.150400.24.78.1, 5.14.21-150500.55.100.1.150500.6.47.1
kernel-default-base - addressed in versions 5.14.21-150400.24.158.1.150400.24.78.1, 5.14.21-150500.55.100.1.150500.6.47.1
kernel-rt-devel - update to 5.14.21-150500.13.91.1
kernel-rt_debug-devel - update to 5.14.21-150500.13.91.1
dlm-kmp-rt - update to 5.14.21-150500.13.91.1
reiserfs-kmp-rt - update to 5.14.21-150500.13.91.1
kernel-rt_debug-devel-debuginfo - update to 5.14.21-150500.13.91.1
reiserfs-kmp-rt-debuginfo - update to 5.14.21-150500.13.91.1
kernel-rt-vdso-debuginfo - update to 5.14.21-150500.13.91.1
kernel-rt-extra - update to 5.14.21-150500.13.91.1
gfs2-kmp-rt - update to 5.14.21-150500.13.91.1
kernel-rt-livepatch - update to 5.14.21-150500.13.91.1
kernel-rt-vdso - update to 5.14.21-150500.13.91.1
kernel-rt_debug - update to 5.14.21-150500.13.91.1
ocfs2-kmp-rt - update to 5.14.21-150500.13.91.1
kernel-devel-rt - update to 5.14.21-150500.13.91.1
kernel-rt-optional-debuginfo - update to 5.14.21-150500.13.91.1
kernel-syms-rt - update to 5.14.21-150500.13.91.1
kernel-rt_debug-debugsource - update to 5.14.21-150500.13.91.1
ocfs2-kmp-rt-debuginfo - update to 5.14.21-150500.13.91.1
kernel-rt-devel-debuginfo - update to 5.14.21-150500.13.91.1
kernel-rt_debug-vdso - update to 5.14.21-150500.13.91.1
kernel-rt-livepatch-devel - update to 5.14.21-150500.13.91.1
kernel-rt-optional - update to 5.14.21-150500.13.91.1
cluster-md-kmp-rt-debuginfo - update to 5.14.21-150500.13.91.1
gfs2-kmp-rt-debuginfo - update to 5.14.21-150500.13.91.1
kernel-rt_debug-debuginfo - update to 5.14.21-150500.13.91.1
kselftests-kmp-rt-debuginfo - update to 5.14.21-150500.13.91.1
kernel-rt-extra-debuginfo - update to 5.14.21-150500.13.91.1
dlm-kmp-rt-debuginfo - update to 5.14.21-150500.13.91.1
kernel-rt_debug-vdso-debuginfo - update to 5.14.21-150500.13.91.1
kselftests-kmp-rt - update to 5.14.21-150500.13.91.1
cluster-md-kmp-rt - update to 5.14.21-150500.13.91.1
kernel-debug-vdso - update to 5.14.21-150500.55.100.1
kernel-default-vdso - update to 5.14.21-150500.55.100.1
kernel-kvmsmall-vdso-debuginfo - update to 5.14.21-150500.55.100.1
kernel-kvmsmall-vdso - update to 5.14.21-150500.55.100.1
kernel-default-vdso-debuginfo - update to 5.14.21-150500.55.100.1
kernel-debug-vdso-debuginfo - update to 5.14.21-150500.55.100.1

External References

Related Security Bulletins