{"id":"CVE-2026-89568","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nkho: fix size calculation in kho_preserved_memory_reserve()\n\nkho_preserved_memory_reserve() calculates the size of a preservation by\ndoing 1 << (order + PAGE_SHIFT)","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nkho: fix size calculation in kho_preserved_memory_reserve()\n\nkho_preserved_memory_reserve() calculates the size of a preservation by\ndoing 1 << (order + PAGE_SHIFT). Si…","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","cwe":["CWE-1335"],"vendor":"Linux","product":"Linux","affected":["Linux >= fc33e4b44b2717feba2f6f07ce7943a96499c9ec < 0692a8fdf0222af130c8ea97426f1c3bf3814905","Linux >= fc33e4b44b2717feba2f6f07ce7943a96499c9ec < 42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1","Linux >= fc33e4b44b2717feba2f6f07ce7943a96499c9ec < 3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded","Linux 6.16"],"published":"2026-09-11","updated":"2026-10-15","sourceUpdated":"2026-10-15T11:17:54.227","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89568","references":[{"url":"https://git.kernel.org/stable/c/0692a8fdf0222af130c8ea97426f1c3bf3814905","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"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"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00206,"epssPercentile":0.10638,"cvssSource":"vendor","ingestedAt":"2026-09-14T11:11:19.886Z","slug":"CVE-2026-89568","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nkho: fix size calculation in kho_preserved_memory_reserve()\n\nkho_preserved_memory_reserve() calculates the size of a preservation by\ndoing 1 << (order + PAGE_SHIFT). Since the '1' is a 32-bit integer, it\ncan only be shifted by 31. That is, it will only work for preservations\nup to 2 GiB. Larger preservations will trigger undefined behaviour.\n\nWhile preservations larger than 2 GiB can't be obtained via folios\ncurrently, they can be obtained via kho_preserve_pages().\n\nFor example, memblock reserve_mem uses kho_preserve_pages().\nReservations larger than 2 GiB are valid and will trigger this bug if\nproperly aligned.\n\nFix it by using 1UL for shifting.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\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)","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"}]}