A high-severity out-of-bounds memory read vulnerability in the Linux kernel CXL subsystem potentially exposes sensitive system information to local attackers.

The vulnerability exists in the cxl_rch_get_aer_info function, which incorrectly calculates the size of the AER register block. A local user with low privileges can trigger this out-of-bounds read to potentially access sensitive memory or cause a system crash.

Successful exploitation of this vulnerability allows a local attacker to read unauthorized memory segments, which may lead to the disclosure of sensitive kernel-level information. Furthermore, the flaw can be leveraged to cause a kernel panic, resulting in denial of service for the affected system. With a CVSS score of 7.1, this vulnerability poses a significant risk to the availability and confidentiality of infrastructure running on vulnerable kernel versions.

Immediate Action: Update your Linux kernel to version 6.18.51, 7.2.4, or later versions where the fix has been backported.

Proactive Monitoring: Monitor system logs for kernel oops or unexpected service restarts that may indicate attempted exploitation of memory-related vulnerabilities.

Compensating Controls: Restrict local shell access to only essential users, as the attack vector requires local privileges to trigger the vulnerable code path.

Public Exploit Available: Unknown

Given the potential for kernel-level information disclosure and system instability, administrators should prioritize patching the Linux kernel across all affected environments. While the attack requires local access, it remains a serious concern for multi-user systems or environments where local privilege boundaries are critical. Ensure that testing is performed on non-production systems before deploying the kernel update to production hardware.