Out-of-bounds write in Linux kernel - CVE-2026-63898

Vulnerability identifier: #VU138751

CSH Severity: Medium

CVSS v4: 5.1 [CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-63898

CWE-ID: CWE-787

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows an attacker with physical access to cause memory corruption.

The vulnerability exists due to memory corruption in the mct_u232 USB serial driver when handling a malicious USB device that reports a smaller endpoint maximum packet size than expected. An attacker with physical access can connect a specially crafted USB device to cause memory corruption.

Linux kernel
openEuler
Ubuntu
kernel-debugsource
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debuginfo
bpftool-debuginfo
bpftool
kernel
kernel-extra-modules
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-debugsource - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
python3-perf-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
python3-perf - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
perf-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
perf - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools-devel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-source - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-headers - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-devel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
bpftool-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
bpftool - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
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/39e295a91e80f3b91f61c7ada2bde434dcaba20d
• https://git.kernel.org/stable/c/57f332af1745014cd7e40414814ffaa6bc7d3b5b
• https://git.kernel.org/stable/c/6cb48f8890f9b2051d7c34823057296a536a31c5
• https://git.kernel.org/stable/c/90dbad14b109e5fdfb4934ff61e561d11ba3742d
• https://git.kernel.org/stable/c/915b36d701950503c4ea0f6e314b10868e59fce3
• https://git.kernel.org/stable/c/94edbbc5fe00d03cfe1d4e690d7d2cd36317a935
• https://git.kernel.org/stable/c/bd2ddb3fe9052ad8703593bbec26ecc7ca92869e
• https://git.kernel.org/stable/c/d8fdf33d6fcfb90cbec26299baf2352c84b2d768

• Out-of-bounds write 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
• openEuler 24.03 LTS SP3 update for kernel