CVE-2026-23223

Kernel memory corruption via freed XFS scrub cursor

Published Feb 18, 2026 · Updated Feb 18, 2026

Use-after-free in Linux Kernel XFS metadata scrubbing allows local users to corrupt kernel memory during an online scrub operation. The xchk_btree_check_block_owner function dereferences bs->cur while testing whether it aliases an allocation-group btree cursor that has already been freed. Reachability requires CAP_SYS_ADMIN in the initial user namespace and an XFS scrub request; public sources do not establish privilege escalation.

CVSS severity7.8
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Kernel XFS metadata scrubbing allows local users to corrupt kernel memory during an online scrub operation. The xchk_btree_check_block_owner function dereferences bs->cur while testing whether it aliases an allocation-group btree cursor that has already been freed. Reachability requires CAP_SYS_ADMIN in the initial user namespace and an XFS scrub request; public sources do not establish privilege escalation.

The record

CVE
CVE-2026-23223
Published
Feb 18, 2026
Updated
Feb 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Feb 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1d411278dda293a507cb794db7d9ed3511c685c6
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ba5264610423d9653aa36920520902d83841bcfd
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ed82e7949f5cac3058f4100f3cd670531d41a266

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1d411278dda293a507cb794db7d9ed3511c685c6; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ba5264610423d9653aa36920520902d83841bcfd; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ed82e7949f5cac3058f4100f3cd670531d41a266

Published CVSS scores

5.5Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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

CWE-416Use After Free

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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