CVE-2026-52944Network attack vector

File attribute modification via unchecked FSCTL_SET_SPARSE

Published Jun 24, 2026 · Updated Jun 24, 2026

Authorization bypass in ksmbd in affected Linux Kernel releases allows remote authenticated users to modify file sparse attributes. fsctl_set_sparse() persists the requested sparse attribute through an extended attribute without checking share writability or FILE_WRITE_DATA and FILE_WRITE_ATTRIBUTES access. The caller must hold an open SMB file handle; the demonstrated consequence is unauthorized sparse-attribute modification, including on read-only shares.

CVSS severity5.5
Medium
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

Authorization bypass in ksmbd in affected Linux Kernel releases allows remote authenticated users to modify file sparse attributes. fsctl_set_sparse() persists the requested sparse attribute through an extended attribute without checking share writability or FILE_WRITE_DATA and FILE_WRITE_ATTRIBUTES access. The caller must hold an open SMB file handle; the demonstrated consequence is unauthorized sparse-attribute modification, including on read-only shares.

The record

CVE
CVE-2026-52944
Published
Jun 24, 2026
Updated
Jun 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-285, CWE-306, T1565.001
Attack vector
network
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=5.15
  2. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <3127a884525dc8ca4def73254bfcd3ccef0bf812
  3. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <aef151bcfa494bfe983669de2726734b534adb73
  4. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <cc57232cae23c0df91b4a59d0f519141ce9b5b02
  5. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <de9eb0b44fa9123170e6245b49638e0e453c10f8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.15; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <3127a884525dc8ca4def73254bfcd3ccef0bf812; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <aef151bcfa494bfe983669de2726734b534adb73; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <cc57232cae23c0df91b4a59d0f519141ce9b5b02; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <de9eb0b44fa9123170e6245b49638e0e453c10f8

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.3Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization
CWE-306Missing Authentication for Critical Function
T1565.001Stored Data Manipulation

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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