CVE-2025-68809Network attack vector

Remote file deletion via unsynchronized ksmbd flags

Published Jan 13, 2026 · Updated Jan 13, 2026

Race condition in Linux Kernel ksmbd allows remote attackers to delete shared files through concurrent SMB2 requests. Unsynchronized reads and writes to ksmbd_inode->m_flags in vfs_cache.c can lose or stale delete-on-close and pending-delete bits. A writable share and delete-capable handles are normally required, but guest-writable shares permit unauthenticated reachability; impact is limited to file integrity and dependent-service availability.

CVSS severity9.1
Critical
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux Kernel ksmbd allows remote attackers to delete shared files through concurrent SMB2 requests. Unsynchronized reads and writes to ksmbd_inode->m_flags in vfs_cache.c can lose or stale delete-on-close and pending-delete bits. A writable share and delete-capable handles are normally required, but guest-writable shares permit unauthenticated reachability; impact is limited to file integrity and dependent-service availability.

The record

CVE
CVE-2025-68809
Published
Jan 13, 2026
Updated
Jan 13, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1485
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 13, 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 <5adad9727a815c26013b0d41cfee92ffa7d4037c
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <991f8a79db99b14c48d20d2052c82d65b9186cad
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ccc78781041589ea383e61d5d7a1e9a31b210b93
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ee63729760f5b61a66f345c54dc4c7514e62383d

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5adad9727a815c26013b0d41cfee92ffa7d4037c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <991f8a79db99b14c48d20d2052c82d65b9186cad; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ccc78781041589ea383e61d5d7a1e9a31b210b93; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ee63729760f5b61a66f345c54dc4c7514e62383d

Published CVSS scores

9.1UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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