CVE-2026-23225

Kernel memory corruption via stale MMCID ownership

Published Feb 18, 2026 · Updated Feb 18, 2026

Out-of-bounds access in Linux Kernel 6.19 allows local users to corrupt kernel memory through an MMCID mode-switch race. sched_mm_cid_exit() calls mm_drop_cid_on_cpu() after a per-CPU-to-per-task transition without confirming ONCPU ownership, so a retained MM_CID_TRANSIT bit becomes an enormous clear_bit() index. Triggering the flaw requires low-privileged local execution and a specific cross-CPU task-exit sequence; the resulting write can corrupt kernel memory or interrupt the system.

CVSS severity7.8
High
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Linux Kernel 6.19 allows local users to corrupt kernel memory through an MMCID mode-switch race. sched_mm_cid_exit() calls mm_drop_cid_on_cpu() after a per-CPU-to-per-task transition without confirming ONCPU ownership, so a retained MM_CID_TRANSIT bit becomes an enormous clear_bit() index. Triggering the flaw requires low-privileged local execution and a specific cross-CPU task-exit sequence; the resulting write can corrupt kernel memory or interrupt the system.

The record

CVE
CVE-2026-23225
Published
Feb 18, 2026
Updated
Feb 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

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

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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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <81f29975631db8a78651b3140ecd0f88ffafc476

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <81f29975631db8a78651b3140ecd0f88ffafc476

Published CVSS scores

7.8kernel.orgCVSS: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
Privilegesauthenticated
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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