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

Vulnerability from cvelistv5 – Published: 2026-01-13 15:29 – Updated: 2026-02-09 08:33
VLAI?
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 ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: f44158485826c076335d6860d35872271a83791d , < 5adad9727a815c26013b0d41cfee92ffa7d4037c (git)
Affected: f44158485826c076335d6860d35872271a83791d , < ccc78781041589ea383e61d5d7a1e9a31b210b93 (git)
Affected: f44158485826c076335d6860d35872271a83791d , < ee63729760f5b61a66f345c54dc4c7514e62383d (git)
Affected: f44158485826c076335d6860d35872271a83791d , < 991f8a79db99b14c48d20d2052c82d65b9186cad (git)
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    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)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/vfs_cache.c"
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          "vendor": "Linux",
          "versions": [
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              "version": "0",
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              "status": "unaffected",
              "version": "6.12.64",
              "versionType": "semver"
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              "version": "6.18.3",
              "versionType": "semver"
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              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
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                  "versionEndExcluding": "6.6.120",
                  "versionStartIncluding": "5.15",
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      "descriptions": [
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          "lang": "en",
          "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-09T08:33:58.311Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5adad9727a815c26013b0d41cfee92ffa7d4037c"
        },
        {
          "url": "https://git.kernel.org/stable/c/ccc78781041589ea383e61d5d7a1e9a31b210b93"
        },
        {
          "url": "https://git.kernel.org/stable/c/ee63729760f5b61a66f345c54dc4c7514e62383d"
        },
        {
          "url": "https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad"
        }
      ],
      "title": "ksmbd: vfs: fix race on m_flags in vfs_cache",
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        "engine": "bippy-1.2.0"
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68809",
    "datePublished": "2026-01-13T15:29:15.817Z",
    "dateReserved": "2025-12-24T10:30:51.047Z",
    "dateUpdated": "2026-02-09T08:33:58.311Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-68809\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-01-13T16:16:03.080\",\"lastModified\":\"2026-01-14T16:26:00.933\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"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.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/5adad9727a815c26013b0d41cfee92ffa7d4037c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ccc78781041589ea383e61d5d7a1e9a31b210b93\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ee63729760f5b61a66f345c54dc4c7514e62383d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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