CVE-2026-89442: Linux kernel · platform/x86: ISST: Validate socket ID in clos_assoc ioctl
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 28 Oct 2026, 01:00 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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().
References
- ubuntu.com/security/CVE-2026-89442 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89442 (opens in a new tab)
- git.kernel.org/linus/a89f07db0cb95c54dac4a8406c79a04e44a73c3c (opens in a new tab)
- git.kernel.org/stable/c/0d90ab5f80e19cddfeb0c9fab47a1f34aa932075 (opens in a new tab)
- git.kernel.org/stable/c/207b4dc6eb100141b122b2602504a1429a4b6558 (opens in a new tab)
- git.kernel.org/stable/c/82e707eff9e3b7ef6d96ecc23ea8876d20c7d6ca (opens in a new tab)
- git.kernel.org/stable/c/a89f07db0cb95c54dac4a8406c79a04e44a73c3c (opens in a new tab)