CVE-2026-89568
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.
How to fix
- Linux Linux0692a8fdf0222af130c8ea97426f1c3bf3814905, 42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1, 3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | fc33e4b44b2717feba2f6f07ce7943a96499c9ec ≤ v < 0692a8fdf0222af130c8ea97426f1c3bf3814905, fc33e4b44b2717feba2f6f07ce7943a96499c9ec ≤ v < 42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1, fc33e4b44b2717feba2f6f07ce7943a96499c9ec ≤ v < 3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded, 6.16 | 0692a8fdf0222af130c8ea97426f1c3bf3814905, 42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1, 3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded |
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