CVE-2026-68457Network attack vector

File corruption via privileged FSCTL worker credentials

Published Aug 15, 2026 · Updated Aug 15, 2026

Privilege context error in Linux ksmbd allows remote attackers to corrupt files on writable SMB shares through crafted FSCTL requests. The SMB2 IOCTL path invokes SET_SPARSE, SET_ZERO_DATA, and SET_COMPRESSION VFS helpers with privileged worker credentials rather than the credentials captured when the handle was opened. A valid SMB session, writable tree, and writable handle are required; guest-writable shares permit remote attackers to change protected metadata or zero and punch arbitrary file ranges.

CVSS severity9.1
Critical
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege context error in Linux ksmbd allows remote attackers to corrupt files on writable SMB shares through crafted FSCTL requests. The SMB2 IOCTL path invokes SET_SPARSE, SET_ZERO_DATA, and SET_COMPRESSION VFS helpers with privileged worker credentials rather than the credentials captured when the handle was opened. A valid SMB session, writable tree, and writable handle are required; guest-writable shares permit remote attackers to change protected metadata or zero and punch arbitrary file ranges.

The record

CVE
CVE-2026-68457
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-270, T1485
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=0 <6.1.178
  2. Affected versionversion=0 <6.12.97
  3. Affected versionversion=0 <6.18.40
  4. Affected versionversion=0 <6.6.145
  5. Affected versionversion=0 <7.1.5
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1e112c47ec5dd1942e2d4ca6e8e9b712238e20c2
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a8c18434e1f0d9f7989170bdb0490c0160baf065
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c6394bcaf254c5baf9aff43376020be5db6d3316
  9. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <cfb2c6f71d61ed807c9d7a7af331d406f1f31877
  10. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e205f3e7e8c31a47cd11efb6cf663a527177e432
  11. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fb1cae6302d58414ddf029e3f642711bd30243f7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0 <6.1.178; version=0 <6.12.97; version=0 <6.18.40; version=0 <6.6.145; version=0 <7.1.5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1e112c47ec5dd1942e2d4ca6e8e9b712238e20c2; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a8c18434e1f0d9f7989170bdb0490c0160baf065; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c6394bcaf254c5baf9aff43376020be5db6d3316; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <cfb2c6f71d61ed807c9d7a7af331d406f1f31877; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e205f3e7e8c31a47cd11efb6cf663a527177e432; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fb1cae6302d58414ddf029e3f642711bd30243f7

Published CVSS scores

9.1Linux Kernel CVE TeamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
9.1Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
6.5Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/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.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-270Privilege Context Switching Error
T1485Data Destruction

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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