# CVE-2026-89568: linux: In the Linux kernel, the following vulnerability has been resolved:  kho: fix size calculation in kho_preserved_memor...

CVE-2026-89568 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89568 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-89568
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  kho: fix size calculation in kho_preserved_memory_reserve()  kho_preserved_memory_reserve() calculates the size of a preservation by doing 1 << (order + PAGE_SHIFT). Since the '1' is a 32-bit integer, it can only be shifted by 31. That is, it will only work for preservations up to 2 GiB. Larger preservations will trigger undefined behaviour.  While preservations larger than 2 GiB can't be obtained via folios currently, they can be obtained via kho_preserve_pages().  For example, memblock reserve_mem uses kho_preserve_pages(). Reservations larger than 2 GiB are valid and will trigger this bug if properly aligned.  Fix it by using 1UL for shifting.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89568](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89568.md) | Sep 23, 2026 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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