{"id":"CVE-2026-89568","title":"kernel: kho: fix size calculation in kho_preserved_memory_reserve() (CVE-2026-89568)","summary":"A flaw was found in the Linux kernel. The `kho_preserved_memory_reserve()` function, responsible for reserving memory, incorrectly calculates the size of these reservations. This issue arises because it uses a 32-bit integer for bit shifti…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":"CWE-1335","vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","affected":["openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-18","sourceUpdated":"2026-09-18T22:07:22+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89568.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89568.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89568"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532296"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89568"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89568"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89568.mbox"},{"url":"https://git.kernel.org/stable/c/3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded"},{"url":"https://git.kernel.org/stable/c/42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00189,"epssPercentile":0.08807,"ingestedAt":"2026-09-14T11:11:19.886Z","slug":"CVE-2026-89568","body":"## Overview\n\nA flaw was found in the Linux kernel. The `kho_preserved_memory_reserve()` function, responsible for reserving memory, incorrectly calculates the size of these reservations. This issue arises because it uses a 32-bit integer for bit shifting, which limits the maximum reservation size to 2 Gigabytes (GiB). Consequently, attempts to reserve memory larger than 2 GiB can lead to undefined behavior, potentially causing system instability or a denial of service.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89568.json)\n\n**kernel: kho: fix size calculation in kho_preserved_memory_reserve()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.\n\nNot affected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nRefer to the advisory for fix availability.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":208099,"id":"CVE-2026-89568","ts":1789922708632,"field":"cvss","old":"4.4","new":"5.5"},{"seq":204021,"id":"CVE-2026-89568","ts":1789490231081,"field":"cvss","old":null,"new":"4.4"},{"seq":204020,"id":"CVE-2026-89568","ts":1789490231081,"field":"severity","old":"none","new":"medium"},{"seq":147424,"id":"CVE-2026-89568","ts":1789270210854,"field":"cvss","old":null,"new":"4.4"},{"seq":147423,"id":"CVE-2026-89568","ts":1789270210854,"field":"severity","old":"none","new":"medium"},{"seq":109182,"id":"CVE-2026-89568","ts":1789183730632,"field":"cvss","old":null,"new":"4.4"},{"seq":109181,"id":"CVE-2026-89568","ts":1789183730632,"field":"severity","old":"none","new":"medium"}]}