CVE-2026-89438

A flaw was found in the Linux kernel, specifically within the Intel Speed Select Technology (ISST) component. This vulnerability arises from insufficient validation of input values, such as logical CPU ID and CLOS ID, used in the core power feature. A local attacker could exploit this by providing invalid input, which might lead to incorrect calculations for memory-mapped I/O (MMIO) offsets. This could result in memory corruption, potentially allowing for system instability, unauthorized information access, or an increase in privileges.

A MODERATE severity flaw was found in the Linux kernel's Intel Speed Select Technology (ISST) driver, affecting the kernel packages that Red Hat ships in Red Hat Enterprise Linux 9 and 10 and in the RHEL CoreOS kernels used by OpenShift Container Platform 4.16 and later. The ISST core power feature fails to validate the logical CPU ID and CLOS ID supplied by userspace before using those values to calculate a memory-mapped I/O (MMIO) offset. A local attacker with sufficient privileges to access the ISST interface could submit out-of-range logical CPU or CLOS IDs, causing an out-of-bounds write and kernel memory corruption, which could result in a system crash or denial of service, and potentially in information disclosure or privilege escalation. Red Hat rated this flaw MODERATE (CVSS 5.5, CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) because exploitation requires local access with privileges and the primary impact is to system availability. Red Hat Enterprise Linux 6, 7, and 8, and OpenShift Container Platform 4.12 through 4.15, are not affected because the vulnerable code is not present in the kernel versions they ship. For the affected Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 10, and OpenShift Container Platform 4.16 and later streams, the fix is deferred because the flaw is MODERATE severity with a CVSS score below 7.0, below the threshold at which Red Hat prioritizes filing fixes for this component. The residual risk is that a privileged local user on an affected system could trigger kernel memory corruption or a denial of service.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.