CVE-2024-40949

Kernel crash via cleared shmem memcg metadata

Published Jul 12, 2024 · Updated Aug 5, 2026

Improper memory handling in Linux kernel 6.7 through 6.9.6 allows local users to crash the kernel through a shmem folio replacement. mem_cgroup_migrate clears the old folio's memcg metadata before shmem_replace_folio frees it, causing lookup of the wrong lruvec and acquisition of the wrong LRU lock. The path requires low-privileged local execution and shmem swap-in with folio replacement; exploitation can corrupt LRU statistics or crash the kernel.

CVSS severity7.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper memory handling in Linux kernel 6.7 through 6.9.6 allows local users to crash the kernel through a shmem folio replacement. mem_cgroup_migrate clears the old folio's memcg metadata before shmem_replace_folio frees it, causing lookup of the wrong lruvec and acquisition of the wrong LRU lock. The path requires low-privileged local execution and shmem swap-in with folio replacement; exploitation can corrupt LRU statistics or crash the kernel.

The record

CVE
CVE-2024-40949
Published
Jul 12, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=6.7
  2. Affected versionversion=85ce2c517ade0d51b7ad95f2e88be9bbe294379a <8c6c3719ebb7913f8a665d11816d2e38b0eadbab
  3. Affected versionversion=85ce2c517ade0d51b7ad95f2e88be9bbe294379a <9094b4a1c76cfe84b906cc152bab34d4ba26fa5c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.7; version=85ce2c517ade0d51b7ad95f2e88be9bbe294379a <8c6c3719ebb7913f8a665d11816d2e38b0eadbab; version=85ce2c517ade0d51b7ad95f2e88be9bbe294379a <9094b4a1c76cfe84b906cc152bab34d4ba26fa5c

Published CVSS scores

7.8Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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