Vulnerability-Lookup

GHSA-FFPF-RF35-3FHQ

Vulnerability from github – Published: 2026-01-13 18:31 – Updated: 2026-07-30 06:32

Details

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: vfs: fix race on m_flags in vfs_cache

ksmbd maintains delete-on-close and pending-delete state in ksmbd_inode->m_flags. In vfs_cache.c this field is accessed under inconsistent locking: some paths read and modify m_flags under ci->m_lock while others do so without taking the lock at all.

Examples:

ksmbd_query_inode_status() and __ksmbd_inode_close() use ci->m_lock when checking or updating m_flags.
ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close() used to read and modify m_flags without ci->m_lock.

This creates a potential data race on m_flags when multiple threads open, close and delete the same file concurrently. In the worst case delete-on-close and pending-delete bits can be lost or observed in an inconsistent state, leading to confusing delete semantics (files that stay on disk after delete-on-close, or files that disappear while still in use).

Fix it by:

Making ksmbd_query_inode_status() look at m_flags under ci->m_lock after dropping inode_hash_lock.
Adding ci->m_lock protection to all helpers that read or modify m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).
Keeping the existing ci->m_lock protection in __ksmbd_inode_close(), and moving the actual unlink/xattr removal outside the lock.

This unifies the locking around m_flags and removes the data race while preserving the existing delete-on-close behaviour.

Severity

9.1 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68809"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-01-13T16:16:03Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: vfs: fix race on m_flags in vfs_cache\n\nksmbd maintains delete-on-close and pending-delete state in\nksmbd_inode-\u003em_flags. In vfs_cache.c this field is accessed under\ninconsistent locking: some paths read and modify m_flags under\nci-\u003em_lock while others do so without taking the lock at all.\n\nExamples:\n\n - ksmbd_query_inode_status() and __ksmbd_inode_close() use\n   ci-\u003em_lock when checking or updating m_flags.\n - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),\n   ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close()\n   used to read and modify m_flags without ci-\u003em_lock.\n\nThis creates a potential data race on m_flags when multiple threads\nopen, close and delete the same file concurrently. In the worst case\ndelete-on-close and pending-delete bits can be lost or observed in an\ninconsistent state, leading to confusing delete semantics (files that\nstay on disk after delete-on-close, or files that disappear while still\nin use).\n\nFix it by:\n\n - Making ksmbd_query_inode_status() look at m_flags under ci-\u003em_lock\n   after dropping inode_hash_lock.\n - Adding ci-\u003em_lock protection to all helpers that read or modify\n   m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),\n   ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).\n - Keeping the existing ci-\u003em_lock protection in __ksmbd_inode_close(),\n   and moving the actual unlink/xattr removal outside the lock.\n\nThis unifies the locking around m_flags and removes the data race while\npreserving the existing delete-on-close behaviour.",
  "id": "GHSA-ffpf-rf35-3fhq",
  "modified": "2026-07-30T06:32:28Z",
  "published": "2026-01-13T18:31:04Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68809"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5adad9727a815c26013b0d41cfee92ffa7d4037c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ccc78781041589ea383e61d5d7a1e9a31b210b93"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee63729760f5b61a66f345c54dc4c7514e62383d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-68809 (GCVE-0-2025-68809)

Vulnerability from cvelistv5 – Published: 2026-01-13 15:29 – Updated: 2026-08-05 12:11

Title

ksmbd: vfs: fix race on m_flags in vfs_cache

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: vfs: fix race on m_flags in vfs_cache ksmbd maintains delete-on-close and pending-delete state in ksmbd_inode->m_flags. In vfs_cache.c this field is accessed under inconsistent locking: some paths read and modify m_flags under ci->m_lock while others do so without taking the lock at all. Examples: - ksmbd_query_inode_status() and __ksmbd_inode_close() use ci->m_lock when checking or updating m_flags. - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close() used to read and modify m_flags without ci->m_lock. This creates a potential data race on m_flags when multiple threads open, close and delete the same file concurrently. In the worst case delete-on-close and pending-delete bits can be lost or observed in an inconsistent state, leading to confusing delete semantics (files that stay on disk after delete-on-close, or files that disappear while still in use). Fix it by: - Making ksmbd_query_inode_status() look at m_flags under ci->m_lock after dropping inode_hash_lock. - Adding ci->m_lock protection to all helpers that read or modify m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()). - Keeping the existing ci->m_lock protection in __ksmbd_inode_close(), and moving the actual unlink/xattr removal outside the lock. This unifies the locking around m_flags and removes the data race while preserving the existing delete-on-close behaviour.

Severity

9.1 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/5adad9727a815c260…
https://git.kernel.org/stable/c/ccc78781041589ea3…
https://git.kernel.org/stable/c/ee63729760f5b61a6…
https://git.kernel.org/stable/c/991f8a79db99b14c4…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f44158485826c076335d6860d35872271a83791d , < 5adad9727a815c26013b0d41cfee92ffa7d4037c (git) Affected: f44158485826c076335d6860d35872271a83791d , < ccc78781041589ea383e61d5d7a1e9a31b210b93 (git) Affected: f44158485826c076335d6860d35872271a83791d , < ee63729760f5b61a66f345c54dc4c7514e62383d (git) Affected: f44158485826c076335d6860d35872271a83791d , < 991f8a79db99b14c48d20d2052c82d65b9186cad (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (semver) Unaffected: 6.6.120 , ≤ 6.6.* (semver) Unaffected: 6.12.64 , ≤ 6.12.* (semver) Unaffected: 6.18.3 , ≤ 6.18.* (semver) Unaffected: 6.19 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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                  "versionStartIncluding": "5.15",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: vfs: fix race on m_flags in vfs_cache\n\nksmbd maintains delete-on-close and pending-delete state in\nksmbd_inode-\u003em_flags. In vfs_cache.c this field is accessed under\ninconsistent locking: some paths read and modify m_flags under\nci-\u003em_lock while others do so without taking the lock at all.\n\nExamples:\n\n - ksmbd_query_inode_status() and __ksmbd_inode_close() use\n   ci-\u003em_lock when checking or updating m_flags.\n - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),\n   ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close()\n   used to read and modify m_flags without ci-\u003em_lock.\n\nThis creates a potential data race on m_flags when multiple threads\nopen, close and delete the same file concurrently. In the worst case\ndelete-on-close and pending-delete bits can be lost or observed in an\ninconsistent state, leading to confusing delete semantics (files that\nstay on disk after delete-on-close, or files that disappear while still\nin use).\n\nFix it by:\n\n - Making ksmbd_query_inode_status() look at m_flags under ci-\u003em_lock\n   after dropping inode_hash_lock.\n - Adding ci-\u003em_lock protection to all helpers that read or modify\n   m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),\n   ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).\n - Keeping the existing ci-\u003em_lock protection in __ksmbd_inode_close(),\n   and moving the actual unlink/xattr removal outside the lock.\n\nThis unifies the locking around m_flags and removes the data race while\npreserving the existing delete-on-close behaviour."
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              "value": "AV:N - The race is reachable through ksmbd SMB2 requests received over TCP, normally port 445, including CREATE, SET_INFO, QUERY_INFO, and CLOSE operations.\nAC:L - An attacker can control both sides by opening multiple handles to the same inode and issuing concurrent requests or disconnects that ksmbd processes on separate workers.\nPR:N - Although a valid session, writable tree connection, and delete-capable handle are normally required, ksmbd supports unauthenticated guest sessions and guest-writable shares. Such deployments let a remote attacker reach the race without possessing credentials.\nUI:N - The attacker can create the necessary handles, race the requests, and trigger final close without any victim action.\nS:U - The affected SMB server, filesystem operations, and resulting data impact remain within the host kernel\u0027s security authority.\nC:N - The raced field is an aligned unsigned flag word, and the affected operations neither expose data nor corrupt pointers, object lifetimes, or adjacent memory.\nI:H - Lost or stale pending-delete and delete-on-close bits can cause attacker-selected files, directories, or alternate data streams to be unlinked despite the intended state, producing persistent data loss in a critical writable share.\nA:H - Unexpected and repeatable deletion of operational files while they are in use can persistently make shared storage or dependent services unavailable."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:11:40.534Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        {
          "url": "https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad"
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      ],
      "title": "ksmbd: vfs: fix race on m_flags in vfs_cache",
      "x_generator": {
        "engine": "bippy-1.2.0"
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    "cveId": "CVE-2025-68809",
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    "dateReserved": "2025-12-24T10:30:51.047Z",
    "dateUpdated": "2026-08-05T12:11:40.534Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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