CVE-2026-89439

A flaw was found in the Linux kernel's Intel Speed Select Technology (ISST) driver. A missing NULL check for isst_common.sst_inst[] during failed socket loading could allow a local attacker to trigger a NULL pointer dereference. This vulnerability could lead to a system crash, resulting in a Denial of Service (DoS).

A low impact flaw was found in the Linux kernel's Intel Speed Select Technology (ISST) TPMI driver (drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c). When a CPU socket fails to load, the driver does not check the corresponding isst_common.sst_inst[] entry for NULL, so a local attacker able to trigger this code path could cause a NULL pointer dereference, crashing the kernel and resulting in denial of service. There is no impact on confidentiality or integrity; the Red Hat CVSS 3.1 base score is 5.5 (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). The vulnerable code is present in Red Hat Enterprise Linux 9.4 and later 9.x update streams, Red Hat Enterprise Linux 10.2 and later, and OpenShift Container Platform 4.16 and later (RHEL CoreOS 9) kernel and kernel-rt builds; these are marked affected with resolution DEFER because the CVSS score is below the threshold at which errata trackers are filed for this severity, and the residual risk is limited to local denial of service. Red Hat Enterprise Linux 6, 7, 8, and 9.2, and OpenShift Container Platform 4.12 through 4.15, are marked not affected because the vulnerable code is not present in those product streams.

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.