Use-after-free in Linux kernel - CVE-2026-63808

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Main Vulnerability Database Vulnerabilities #VU138848

Use-after-free in Linux kernel - CVE-2026-63808

Published: July 21, 2026


Vulnerability identifier: #VU138848
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63808
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in exfat_find_dir_entry() when parsing a crafted exFAT filesystem image. A local user can supply a crafted exFAT image to trigger a kernel fault and cause a denial of service.

The issue occurs on the TYPE_EXTEND path after a directory entry buffer is released and then dereferenced.


Affected software

Linux kernel
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
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Micro Extras
SUSE Linux Micro
Public Cloud Module
Legacy Module
SUSE Linux Enterprise Live Patching
Development Tools Module
Basesystem Module
SUSE Real Time Module
Ubuntu
openEuler
linux-raspi (Ubuntu package)
linux (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-realtime (Ubuntu package)
linux-fips (Ubuntu package)
linux-gkeop (Ubuntu package)
linux-gke (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)
kernel-livepatch-6_4_0-150700_7_75-rt-debuginfo
kernel-livepatch-6_4_0-150700_7_75-rt
kernel-livepatch-SLE15-SP7-RT_Update_20-debugsource
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo
kernel-livepatch-SLE15-SP7_Update_21-debugsource
kernel-livepatch-6_4_0-150700_53_81-default
kernel-tools-devel
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
bpftool
kernel-64kb-debugsource
kernel-kvmsmall-debuginfo
kernel-default
kernel-default-devel-debuginfo
kernel-obs-build-debugsource
kernel-default-debugsource
kernel-default-devel
kernel-syms
kernel-obs-build
kernel-64kb-devel
kernel-kvmsmall
kernel-rt-livepatch
kernel-rt-debugsource
kernel-64kb
kernel-rt-debuginfo
kernel-rt
kernel-devel-rt
kernel-source-rt
kernel-macros
kernel-default-livepatch
kernel-default-debuginfo
kernel-kvmsmall-debugsource
kernel-default-base
gfs2-kmp-rt
cluster-md-kmp-rt-debuginfo
dlm-kmp-rt-debuginfo
ocfs2-kmp-rt
ocfs2-kmp-rt-debuginfo
kernel-syms-rt
kernel-rt-devel-debuginfo
cluster-md-kmp-rt
kernel-rt-devel
dlm-kmp-rt
gfs2-kmp-rt-debuginfo
kernel-zfcpdump-debugsource
reiserfs-kmp-default-debuginfo
kernel-default-livepatch-devel
kernel-64kb-debuginfo
kernel-zfcpdump
kernel-zfcpdump-debuginfo
kernel-default-extra
kernel-default-extra-debuginfo
kernel-azure-devel-debuginfo
kernel-azure-debuginfo
kernel-azure-debugsource
kernel-azure-devel
kernel-azure
dlm-kmp-default-debuginfo
ocfs2-kmp-default
gfs2-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
cluster-md-kmp-default
kernel-64kb-devel-debuginfo
kernel-docs
gfs2-kmp-default
dlm-kmp-default
cluster-md-kmp-default-debuginfo
reiserfs-kmp-default
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-aws-5.15 (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-63808

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-raspi (Ubuntu package) - addressed in versions 5.15.0-1110.113, 7.0.0-1019.19
linux (Ubuntu package) - addressed in versions 5.15.0-194.204, 5.15.0-1111.112, 5.15.0.194.171, 5.15.0.1111.111, 6.8.0-147.147, 7.0.0-31.31~24.04.1, 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12~24.04.1, 7.0.0-1012.12
linux-lowlatency (Ubuntu package) - update to 6.8.0-147.147.1
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1071.79, 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp (Ubuntu package) - update to 6.8.0-1071.79
linux-aws (Ubuntu package) - addressed in versions 5.15.0-194.204~20.04.1, 5.15.0-194.204, 5.15.0-1079.83, 5.15.0-1099.107, 5.15.0-1108.110, 5.15.0-1108.113, 5.15.0-1110.114, 5.15.0-1111.117, 5.15.0-1112.118, 5.15.0-1113.119, 5.15.0-1115.124, 5.15.0-1116.123, 5.15.0-1116.123+fips1, 5.15.0-1116.126+fips1, 5.15.0-1117.127, 5.15.0-1121.130, 5.15.0-1122.131, 5.15.0-1122.131+fips1, 5.15.0.194.159, 5.15.0.1079.82, 5.15.0.1099.98, 5.15.0.1108.104, 5.15.0.1108.112, 5.15.0.1110.107, 5.15.0.1111.110, 5.15.0.1112.111, 5.15.0.1113.109, 5.15.0.1115.119, 5.15.0.1116.106, 5.15.0.1116.112, 5.15.0.1116.119, 5.15.0.1117.114, 5.15.0.1122.106, 5.15.0.1122.120, 6.8.0-1067.70
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1067.68, 7.0.0-1013.13
linux-oracle (Ubuntu package) - update to 6.8.0-1064.67
linux-azure-fde (Ubuntu package) - update to 6.8.0-1069.76
linux-realtime (Ubuntu package) - update to 6.8.1-1062.63
linux-fips (Ubuntu package) - addressed in versions 5.15.0-194.204+fips1, 5.15.0.194.113, 6.8.0-147.147+fips1
linux-gkeop (Ubuntu package) - update to 6.8.0-1052.56
linux-gke (Ubuntu package) - update to 6.8.0-1066.74
linux-azure-fips (Ubuntu package) - update to 6.8.0-1071.79+fips1
linux-aws-fips (Ubuntu package) - update to 6.8.0-1067.70+fips1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1071.79+fips1
kernel-livepatch-6_4_0-150700_7_75-rt-debuginfo - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_75-rt - update to 1-150700.1.3.1
kernel-livepatch-SLE15-SP7-RT_Update_20-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo - update to 1-150700.15.3.1
kernel-livepatch-SLE15-SP7_Update_21-debugsource - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_81-default - update to 1-150700.15.3.1
kernel-tools-devel - update to 5.10.0-337.0.0.238
python3-perf-debuginfo - update to 5.10.0-337.0.0.238
python3-perf - update to 5.10.0-337.0.0.238
perf-debuginfo - update to 5.10.0-337.0.0.238
perf - update to 5.10.0-337.0.0.238
kernel - update to 5.10.0-337.0.0.238
kernel-tools-debuginfo - update to 5.10.0-337.0.0.238
kernel-tools - update to 5.10.0-337.0.0.238
kernel-source - update to 5.10.0-337.0.0.238
kernel-headers - update to 5.10.0-337.0.0.238
kernel-devel - update to 5.10.0-337.0.0.238
kernel-debugsource - update to 5.10.0-337.0.0.238
kernel-debuginfo - update to 5.10.0-337.0.0.238
bpftool-debuginfo - update to 5.10.0-337.0.0.238
bpftool - update to 5.10.0-337.0.0.238
kernel-64kb-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-kvmsmall-debuginfo - update to 6.4.0-52.1
kernel-default - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-devel-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-obs-build-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-syms - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-obs-build - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-64kb-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-kvmsmall - update to 6.4.0-52.1
kernel-rt-livepatch - update to 6.4.0-52.1
kernel-rt-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-64kb - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-rt-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-devel-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-source-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-macros - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-source - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-livepatch - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-kvmsmall-debugsource - update to 6.4.0-52.1
kernel-default-base - addressed in versions 6.4.0-52.1.21.35, 6.4.0-52.1.21.36, 6.4.0-150700.53.81.1.150700.17.45.1
gfs2-kmp-rt - update to 6.4.0-150700.7.75.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.75.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
kernel-syms-rt - update to 6.4.0-150700.7.75.1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.75.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.75.1
kernel-rt-devel - update to 6.4.0-150700.7.75.1
dlm-kmp-rt - update to 6.4.0-150700.7.75.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.81.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.81.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.81.1
kernel-zfcpdump - update to 6.4.0-150700.53.81.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-extra - update to 6.4.0-150700.53.81.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.81.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.81.1
kernel-azure-debugsource - update to 6.4.0-150700.53.81.1
kernel-azure-devel - update to 6.4.0-150700.53.81.1
kernel-azure - 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
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
cluster-md-kmp-default - update to 6.4.0-150700.53.81.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-docs - update to 6.4.0-150700.53.81.1
gfs2-kmp-default - update to 6.4.0-150700.53.81.1
dlm-kmp-default - update to 6.4.0-150700.53.81.1
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
reiserfs-kmp-default - update to 6.4.0-150700.53.81.1
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1057.57, 5.15.0-1068.70, 5.15.0.1057.59, 5.15.0.1068.68, 6.8.0-1035.38
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1068.70~20.04.1
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1110.114~20.04.1
linux-aws-5.15 (Ubuntu package) - addressed in versions 5.15.0-1111.117~20.04.1, 5.15.0-1116.123~20.04.1, 5.15.0-1121.130~20.04.1, 5.15.0-1122.131~20.04.1
linux-oracle-5.15 (Ubuntu package) - addressed in versions 5.15.0-1114.120~20.04.1, 5.15.0.1114.120~20.04.1
linux-gcp-5.15 (Ubuntu package) - addressed in versions 5.15.0-1118.128~20.04.1, 5.15.0.1118.128~20.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
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
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia-7.0 (Ubuntu package) - update to 7.0.0-1018.18~24.04.1
linux-nvidia (Ubuntu package) - update to 7.0.0-1018.18
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2018.18

External References

Related Security Bulletins