CVE-2026-89493Hinoki check available

Kernel memory corruption via unchecked refcount bounds

Published Sep 11, 2026 · Updated Sep 11, 2026

Out-of-bounds access in Linux OCFS2 refcount handling allows local users to corrupt kernel memory through a crafted filesystem image. ocfs2_validate_refcount_block accepts disk-supplied rl_used and rl_count values without checking the record-array capacity or ensuring that usage does not exceed the count. Exploitation requires CAP_SYS_ADMIN to mount the image or raw access to an already-mounted backing device; a reflink operation can then reach an out-of-bounds read and memmove.

CVSS severityUnavailable
Unscored
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Out-of-bounds access in Linux OCFS2 refcount handling allows local users to corrupt kernel memory through a crafted filesystem image. ocfs2_validate_refcount_block accepts disk-supplied rl_used and rl_count values without checking the record-array capacity or ensuring that usage does not exceed the count. Exploitation requires CAP_SYS_ADMIN to mount the image or raw access to an already-mounted backing device; a reflink operation can then reach an out-of-bounds read and memmove.

The record

CVE
CVE-2026-89493
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=2.6.32
  2. Affected versionversion=f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4 <04ead708e13ddcb9c39319cbe02a18cef99cb823
  3. Affected versionversion=f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4 <0761d2c9494424469a0d30a9da3496ca010b0b2d
  4. Affected versionversion=f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4 <4ca62df6bc0708947b48da3f6a712ecb8e73929c
  5. Affected versionversion=f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4 <af56e90cb546cb0c47bef059335365283f61d6a4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.32; version=f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4 <04ead708e13ddcb9c39319cbe02a18cef99cb823; version=f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4 <0761d2c9494424469a0d30a9da3496ca010b0b2d; version=f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4 <4ca62df6bc0708947b48da3f6a712ecb8e73929c; version=f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4 <af56e90cb546cb0c47bef059335365283f61d6a4

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

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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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