CVE-2026-53040

Local disclosure or crash via unchecked bitmap limit

Published Jun 24, 2026 · Updated Jun 24, 2026

Use-after-free in Linux Kernel OCFS2 allows local users to disclose kernel memory or crash the system through a crafted filesystem. The ocfs2_info_freefrag_scan_chain() path trusts the on-disk bg_bits value as a scan limit after non-coherent reads skip descriptor validation. Exploitation requires local low-privileged access to issue OCFS2_IOC_INFO with OCFS2_INFO_FL_NON_COHERENT against the crafted filesystem.

CVSS severity7.1
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 OCFS2 allows local users to disclose kernel memory or crash the system through a crafted filesystem. The ocfs2_info_freefrag_scan_chain() path trusts the on-disk bg_bits value as a scan limit after non-coherent reads skip descriptor validation. Exploitation requires local low-privileged access to issue OCFS2_IOC_INFO with OCFS2_INFO_FL_NON_COHERENT against the crafted filesystem.

The record

CVE
CVE-2026-53040
Published
Jun 24, 2026
Updated
Jun 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 24, 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=3.0
  2. Affected versionversion=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <05d0cbea41167b6b061c6ba5b70ee5a9a7a24c9e
  3. Affected versionversion=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <0998674eec138c55e9e349b9cbd9dbc5129a9cc8
  4. Affected versionversion=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <3e167e230d19cd273108bab2e4c61800fc335ae8
  5. Affected versionversion=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <4c2d62ddde8928db12f4608950b67a20e67deab2
  6. Affected versionversion=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <8f687eeed3da3012152b0f9473f578869de0cd7b
  7. Affected versionversion=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <bb2906a1065ec28de021bac2ed03f2624edd7d07
  8. Affected versionversion=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <bb3c54d1e71578521111f1a1ee7d5f4761a242b8
  9. Affected versionversion=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <e0dcf12665d6dde37facf790803cdad44d5c328c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.0; version=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <05d0cbea41167b6b061c6ba5b70ee5a9a7a24c9e; version=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <0998674eec138c55e9e349b9cbd9dbc5129a9cc8; version=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <3e167e230d19cd273108bab2e4c61800fc335ae8; version=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <4c2d62ddde8928db12f4608950b67a20e67deab2; version=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <8f687eeed3da3012152b0f9473f578869de0cd7b; version=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <bb2906a1065ec28de021bac2ed03f2624edd7d07; version=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <bb3c54d1e71578521111f1a1ee7d5f4761a242b8; version=d24a10b9f8ed548981696cd36e2b4f16e6f360b1 <e0dcf12665d6dde37facf790803cdad44d5c328c

Published CVSS scores

7.1kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 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

CWE-416Use After Free
T1499.004Endpoint Denial of Service: Application 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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