Out-of-bounds read in Linux kernel - CVE-2026-23327

Vulnerability identifier: #VU124523

CSH Severity: Low

CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-23327

CWE-ID: CWE-125

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service, disclose sensitive information, and potentially execute arbitrary code.

The vulnerability exists due to improper input validation in the CXL mailbox command handler when processing user-supplied payloads. A local user can send a specially crafted raw mailbox command with an undersized payload to trigger an out-of-bounds read in the kernel, leading to memory disclosure, system crash, or potential code execution.

The issue specifically occurs in the cxl_payload_from_user_allowed() function, where the payload size is not validated before accessing its contents, resulting in a slab-out-of-bounds read during UUID comparison.

Linux kernel
Anolis OS
bpftool
kernel
kernel-debug
kernel-debug-devel
kernel-devel
kernel-headers
kernel-tools
kernel-tools-libs
kernel-tools-libs-devel
perf
python3-perf

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
bpftool - update to 6.6.102-7
kernel - update to 6.6.102-7
kernel-debug - update to 6.6.102-7
kernel-debug-devel - update to 6.6.102-7
kernel-devel - update to 6.6.102-7
kernel-headers - update to 6.6.102-7
kernel-tools - update to 6.6.102-7
kernel-tools-libs - update to 6.6.102-7
kernel-tools-libs-devel - update to 6.6.102-7
perf - update to 6.6.102-7
python3-perf - update to 6.6.102-7

• https://git.kernel.org/stable/c/60b5d1f68338aff2c5af0113f04aefa7169c50c2
• https://git.kernel.org/stable/c/7c8a7b7f063b7e7ae9bba4cbaa14a5d2fe3a55e1

• Out-of-bounds read in Linux kernel cxl core driver
• Anolis OS update for kernel:6.6