CVE-2026-89442 platform/x86: ISST: Validate socket ID in clos_assoc ioctl
A local attacker can cause a kernel crash by triggering an out-of-bounds access or null pointer dereference in the Intel Speed Select Technology driver.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89442?
CVE-2026-89442 is a high-severity vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
platform/x86: ISST: Validate socket ID in clos_assoc ioctl
isst_if_clos_assoc() validates the user-supplied socket_id with 'socket_id > topology_max_packages()', but isst_common.sst_inst[] is allocated with topology_max_packages() entries, so the valid index range is [0, topology_max_packages()). The '>' comparison lets socket_id == topology_max_packages() pass and index one entry past the array.
In addition, isst_common.sst_inst[socket_id] is NULL for an in-range package that has no bound TPMI SST instance, and the pointer is used without a NULL check. Both the out-of-bounds entry and the NULL pointer are then dereferenced by map_partition_power_domain_id() and the following power_domain_info access.
Reject socket_id >= topology_max_packages() and a NULL sst_inst, matching the checks already performed by get_instance().
Which versions are affected by CVE-2026-89442?
How do I fix CVE-2026-89442?
Apply the vendor's patch.
Is CVE-2026-89442 being exploited?
There is no known exploitation of CVE-2026-89442 in the wild and no public exploit code.
Sources
Also known as AZL-100214, BELL-CVE-2026-89442, DEBIAN-CVE-2026-89442, GHSA-66vv-5f3v-p2fx, UBUNTU-CVE-2026-89442.