CVE-2026-89503

Reader-page size mismatch via subbuffer resize race

Published Sep 11, 2026 · Updated Sep 11, 2026

Race condition in the Linux kernel 6.8 allows attackers to create a ring-buffer reader page with inconsistent allocation metadata. During ring_buffer_alloc_read_page(), a concurrent resize can change subbuf_order after bpage->order is recorded, so alloc_cpu_data() allocates memory at a different order. Triggering the flaw requires the allocation and resize operations to overlap; the published material specifies no resulting crash, disclosure, or code-execution impact.

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

What happened

Race condition in the Linux kernel 6.8 allows attackers to create a ring-buffer reader page with inconsistent allocation metadata. During ring_buffer_alloc_read_page(), a concurrent resize can change subbuf_order after bpage->order is recorded, so alloc_cpu_data() allocates memory at a different order. Triggering the flaw requires the allocation and resize operations to overlap; the published material specifies no resulting crash, disclosure, or code-execution impact.

The record

CVE
CVE-2026-89503
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

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=6.8
  2. Affected versionversion=bce761d757452ba5eb77e11fecc37a04b67494e7 <2dc510957fe8fd098ab3c3147ebdf34d00cd2734
  3. Affected versionversion=bce761d757452ba5eb77e11fecc37a04b67494e7 <53106e9262a310ef2c9a9321168c03705940c678
  4. Affected versionversion=bce761d757452ba5eb77e11fecc37a04b67494e7 <e743527c5bfdceda1095bc0a9e596e2aebb6a9c3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.8; version=bce761d757452ba5eb77e11fecc37a04b67494e7 <2dc510957fe8fd098ab3c3147ebdf34d00cd2734; version=bce761d757452ba5eb77e11fecc37a04b67494e7 <53106e9262a310ef2c9a9321168c03705940c678; version=bce761d757452ba5eb77e11fecc37a04b67494e7 <e743527c5bfdceda1095bc0a9e596e2aebb6a9c3

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
PrivilegesUnavailable
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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