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

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Main Vulnerability Database Vulnerabilities #VU138696

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

Published: July 20, 2026


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

Vulnerability details

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.


Affected software

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

How to mitigate CVE-2026-63959

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
python3-perf-debuginfo - update to 5.10.0-326.0.0.227
python3-perf - 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 - 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
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-gcp (Ubuntu package) - update to 6.8.0-1070.78
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 (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1016.16
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

Related Security Bulletins