CVE-2026-89568

Incorrect memory reservation via 32-bit size shift

Published Sep 11, 2026 · Updated Sep 11, 2026

Integer-size miscalculation in Linux 6.16 allows attackers to reserve the wrong memory size through a large aligned KHO reservation. kho_preserved_memory_reserve() shifts a 32-bit integer by order plus PAGE_SHIFT, producing undefined behavior for reservations of 2 GiB or larger. Reachability requires a properly aligned large reservation through kho_preserve_pages(), including reserve_mem; the kernel can then reserve the wrong amount.

CVSS severityUnavailable
Unscored
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer-size miscalculation in Linux 6.16 allows attackers to reserve the wrong memory size through a large aligned KHO reservation. kho_preserved_memory_reserve() shifts a 32-bit integer by order plus PAGE_SHIFT, producing undefined behavior for reservations of 2 GiB or larger. Reachability requires a properly aligned large reservation through kho_preserve_pages(), including reserve_mem; the kernel can then reserve the wrong amount.

The record

CVE
CVE-2026-89568
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.16
  2. Affected versionversion=fc33e4b44b2717feba2f6f07ce7943a96499c9ec <3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded
  3. Affected versionversion=fc33e4b44b2717feba2f6f07ce7943a96499c9ec <42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=6.16; version=fc33e4b44b2717feba2f6f07ce7943a96499c9ec <3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded; version=fc33e4b44b2717feba2f6f07ce7943a96499c9ec <42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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