Out-of-bounds read in Linux kernel - CVE-2026-63959

Vulnerability identifier: #VU138696

CSH Severity: Low

CVSS v4: 2.4 [CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-63959

CWE-ID: CWE-125

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows an attacker with physical access to disclose sensitive information.

The vulnerability exists due to an out-of-bounds read in the tcpci_maxim RX message processing logic when processing a crafted USB Type-C/Power Delivery frame with a mismatched header data object count. An attacker with physical access can send a specially crafted frame to disclose sensitive information.

The issue occurs when a CRC-valid frame advertises more data objects in the header than are actually present in the message body.

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/0af00f1459f5dd757f0d392f8caa38039561ac62
• https://git.kernel.org/stable/c/9b496e3371c04f0a03b7faa5d2442536d00e3998
• https://git.kernel.org/stable/c/aa2f716327be1818e1cb156da8a2844804aaec2f
• https://git.kernel.org/stable/c/c4ab8e2d4432abb646c5c0687f8dab173da901f9
• https://git.kernel.org/stable/c/dc17721d42e6d89f63572e63add8306a0e15eb3c

• Out-of-bounds read in Linux kernel typec tcpm 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