kho: fix size calculation in kho_preserved_memory_reserve()
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.18.57, 7.2.4, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 6 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89568
- 2026-10-03 Alias added: GHSA-832m-273v-9hpc
- 2026-10-16 Fix available: Linux/Linux@0692a8fdf0222af130c8ea97426f1c3bf3814905, Linux/[email protected] · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
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Sources
- CVE-2026-89568 · CVE Program
- CVE-2026-89568 · NVD
- FIRST EPSS
- GHSA-832m-273v-9hpc · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89568 · Red Hat security data · CC BY 4.0
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