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

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

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.

Linux kernel
openEuler
Ubuntu
kernel-debuginfo
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
bpftool-debuginfo
bpftool
kernel
python3-perf
python3-perf-debuginfo
linux-ibm (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-debuginfo - update to 5.10.0-326.0.0.227
perf-debuginfo - update to 5.10.0-326.0.0.227
perf - update to 5.10.0-326.0.0.227
kernel-tools-devel - update to 5.10.0-326.0.0.227
kernel-tools-debuginfo - update to 5.10.0-326.0.0.227
kernel-tools - update to 5.10.0-326.0.0.227
kernel-source - update to 5.10.0-326.0.0.227
kernel-headers - update to 5.10.0-326.0.0.227
kernel-devel - update to 5.10.0-326.0.0.227
kernel-debugsource - update to 5.10.0-326.0.0.227
bpftool-debuginfo - update to 5.10.0-326.0.0.227
bpftool - update to 5.10.0-326.0.0.227
kernel - update to 5.10.0-326.0.0.227
python3-perf - update to 5.10.0-326.0.0.227
python3-perf-debuginfo - update to 5.10.0-326.0.0.227
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-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/245aba83e3c288e176ed037a1f6b618b09e92ed8
• https://git.kernel.org/stable/c/631b8b7c456567f7a8d26f6fc354c8dd9cc9f832
• https://git.kernel.org/stable/c/70bb9a2661d34b93a9b83cf83e2b76289a712ef0
• https://git.kernel.org/stable/c/82b48d70bced1ec8e5f676d1fd5eccc7a44dc418
• https://git.kernel.org/stable/c/8b93ee5baeef6efabee2c3381907733ad2dbc883
• https://git.kernel.org/stable/c/a093f3e0c03d25a86d747a655d4b9322ffb2ed87
• https://git.kernel.org/stable/c/ed260b56bc9fc878e5dcbb866eab8af0688e0e67
• https://git.kernel.org/stable/c/f06bcaba29707f060706483b2020d3cafbe98f9f

• Out-of-bounds read in Linux kernel usb serial driver
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• openEuler 22.03 LTS SP4 update for kernel
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia