Out-of-bounds read in Linux kernel - CVE-2026-63897

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Main Vulnerability Database Vulnerabilities #VU138750

Out-of-bounds read in Linux kernel - CVE-2026-63897

Published: July 20, 2026


Vulnerability identifier: #VU138750
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63897
CWE-ID: CWE-125
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to an out-of-bounds read in the mct_u232 USB serial driver interrupt-in transfer handler when processing short interrupt-in transfers. A local user can trigger the driver to process a specially crafted short interrupt-in packet to disclose sensitive information.

The issue can lead to stale or uninitialized slab data being exposed to user space.


Affected software

Linux kernel
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Live Patching
Ubuntu
openEuler
kgraft-patch-4_12_14-122_333-default
ocfs2-kmp-default
gfs2-kmp-default
gfs2-kmp-default-debuginfo
kernel-default-devel
ocfs2-kmp-default-debuginfo
cluster-md-kmp-default-debuginfo
kernel-default-base
kernel-syms
kernel-default-base-debuginfo
cluster-md-kmp-default
kernel-default-man
dlm-kmp-default-debuginfo
dlm-kmp-default
kernel-default-debuginfo
kernel-default-kgraft-devel
kernel-default-debugsource
kernel-default-kgraft
kernel-default
kernel-devel
kernel-source
kernel-macros
kernel-default-devel-debuginfo
python3-perf-debuginfo
python3-perf
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-headers
kernel-tools
kernel-tools-debuginfo
kernel-tools-devel
perf
perf-debuginfo
linux (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-gcp (Ubuntu package)
linux-gke (Ubuntu package)
linux-azure (Ubuntu package)
linux-ibm (Ubuntu package)
linux-aws (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-63897

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kgraft-patch-4_12_14-122_333-default - update to 1-8.3.3
ocfs2-kmp-default - update to 4.12.14-122.333.2
gfs2-kmp-default - update to 4.12.14-122.333.2
gfs2-kmp-default-debuginfo - update to 4.12.14-122.333.2
kernel-default-devel - update to 4.12.14-122.333.2
ocfs2-kmp-default-debuginfo - update to 4.12.14-122.333.2
cluster-md-kmp-default-debuginfo - update to 4.12.14-122.333.2
kernel-default-base - update to 4.12.14-122.333.2
kernel-syms - update to 4.12.14-122.333.2
kernel-default-base-debuginfo - update to 4.12.14-122.333.2
cluster-md-kmp-default - update to 4.12.14-122.333.2
kernel-default-man - update to 4.12.14-122.333.2
dlm-kmp-default-debuginfo - update to 4.12.14-122.333.2
dlm-kmp-default - update to 4.12.14-122.333.2
kernel-default-debuginfo - update to 4.12.14-122.333.2
kernel-default-kgraft-devel - update to 4.12.14-122.333.2
kernel-default-debugsource - update to 4.12.14-122.333.2
kernel-default-kgraft - update to 4.12.14-122.333.2
kernel-default - update to 4.12.14-122.333.2
kernel-devel - update to 4.12.14-122.333.2
kernel-source - update to 4.12.14-122.333.2
kernel-macros - update to 4.12.14-122.333.2
kernel-default-devel-debuginfo - update to 4.12.14-122.333.2
python3-perf-debuginfo - update to 5.10.0-326.0.0.227
python3-perf - update to 5.10.0-326.0.0.227
kernel - update to 5.10.0-326.0.0.227
bpftool - update to 5.10.0-326.0.0.227
bpftool-debuginfo - update to 5.10.0-326.0.0.227
kernel-debuginfo - update to 5.10.0-326.0.0.227
kernel-debugsource - update to 5.10.0-326.0.0.227
kernel-devel - update to 5.10.0-326.0.0.227
kernel-headers - update to 5.10.0-326.0.0.227
kernel-source - update to 5.10.0-326.0.0.227
kernel-tools - update to 5.10.0-326.0.0.227
kernel-tools-debuginfo - update to 5.10.0-326.0.0.227
kernel-tools-devel - update to 5.10.0-326.0.0.227
perf - update to 5.10.0-326.0.0.227
perf-debuginfo - update to 5.10.0-326.0.0.227
linux (Ubuntu package) - addressed in versions 5.15.0-195.205~20.04.1, 5.15.0-195.205, 5.15.0-198.208~20.04.1, 5.15.0-198.208+fips1, 5.15.0-1080.84, 5.15.0-1100.108, 5.15.0-1109.111, 5.15.0-1109.114, 5.15.0-1111.115~20.04.1, 5.15.0-1111.115, 5.15.0-1112.118~20.04.1, 5.15.0-1112.118, 5.15.0-1113.119, 5.15.0-1114.120, 5.15.0-1116.125~20.04.1, 5.15.0-1117.124~20.04.1, 5.15.0-1117.124, 5.15.0-1117.124+fips1, 5.15.0-1122.131~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1123.132, 5.15.0-1123.132+fips1, 5.15.0.195.160, 5.15.0.195.205~20.04.1, 5.15.0.198.114, 5.15.0.198.171, 5.15.0.198.208~20.04.1, 5.15.0.1080.83~20.04.1, 5.15.0.1100.99, 5.15.0.1109.105, 5.15.0.1109.113, 5.15.0.1111.108, 5.15.0.1111.115~20.04.1, 5.15.0.1112.111, 5.15.0.1112.118~20.04.1, 5.15.0.1113.112, 5.15.0.1114.110, 5.15.0.1116.120, 5.15.0.1117.113, 5.15.0.1117.120, 5.15.0.1117.124~20.04.1, 5.15.0.1122.131~20.04.1, 5.15.0.1123.107, 5.15.0.1123.121, 5.15.0.1123.132~20.04.1
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112, 7.0.0-1016.16~24.04.1, 7.0.0-1016.16
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-gcp (Ubuntu package) - addressed in versions 5.15.0-1118.128, 5.15.0-1118.128+fips1, 5.15.0.1118.107, 5.15.0.1118.115, 6.8.0-1070.78
linux-gke (Ubuntu package) - addressed in versions 6.8.0-146.146.1~22.04.1, 6.8.0-146.146.1, 6.8.0-1051.55, 6.8.0-1063.66, 6.8.0-1064.67~22.04.1, 6.8.0-1064.67, 6.8.0-1064.67.1, 6.8.0-1065.73, 6.8.0-1066.67
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1068.75~22.04.1, 6.8.0-1068.75, 6.8.0-1069.77+fips1, 6.8.0-1070.78~22.04.1, 6.8.0-1070.78, 7.0.0-1009.9, 7.0.0-1010.10
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
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-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

Related Security Bulletins