{"id":"CVE-2025-68809","state":"PUBLISHED","title":"ksmbd: vfs: fix race on m_flags in vfs_cache","description":"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->m_flags. In vfs_cache.c this field is accessed under\ninconsistent locking: some paths read and modify m_flags under\nci->m_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->m_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->m_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->m_lock\n   after dropping inode_hash_lock.\n - Adding ci->m_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->m_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.","publishedAt":"2026-01-13T15:29:15.817Z","updatedAt":"2026-10-30T12:23:20.102Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"a4fd1fdf505facfae26b5654c9eff321f4cbc1a7","versionType":"git"},{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"5adad9727a815c26013b0d41cfee92ffa7d4037c","versionType":"git"},{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"ccc78781041589ea383e61d5d7a1e9a31b210b93","versionType":"git"},{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"ee63729760f5b61a66f345c54dc4c7514e62383d","versionType":"git"},{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"991f8a79db99b14c48d20d2052c82d65b9186cad","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/vfs_cache.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.120","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.64","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.3","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/vfs_cache.c"]}],"references":["https://git.kernel.org/stable/c/a4fd1fdf505facfae26b5654c9eff321f4cbc1a7","https://git.kernel.org/stable/c/5adad9727a815c26013b0d41cfee92ffa7d4037c","https://git.kernel.org/stable/c/ccc78781041589ea383e61d5d7a1e9a31b210b93","https://git.kernel.org/stable/c/ee63729760f5b61a66f345c54dc4c7514e62383d","https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad"],"weaknesses":[],"ingestedAt":"2026-10-30T12:40:04.423Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/68xxx/CVE-2025-68809.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-68809","state":"PUBLISHED","datePublished":"2026-01-13T15:29:15.817Z","dateUpdated":"2026-10-30T12:23:20.102Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-12-24T10:30:51.047Z"},"containers":{"cna":{"title":"ksmbd: vfs: fix race on m_flags in vfs_cache","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->m_flags. In vfs_cache.c this field is accessed under\ninconsistent locking: some paths read and modify m_flags under\nci->m_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->m_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->m_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->m_lock\n   after dropping inode_hash_lock.\n - Adding ci->m_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->m_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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"a4fd1fdf505facfae26b5654c9eff321f4cbc1a7","versionType":"git"},{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"5adad9727a815c26013b0d41cfee92ffa7d4037c","versionType":"git"},{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"ccc78781041589ea383e61d5d7a1e9a31b210b93","versionType":"git"},{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"ee63729760f5b61a66f345c54dc4c7514e62383d","versionType":"git"},{"version":"f44158485826c076335d6860d35872271a83791d","status":"affected","lessThan":"991f8a79db99b14c48d20d2052c82d65b9186cad","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/vfs_cache.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.120","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.64","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.3","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/vfs_cache.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a4fd1fdf505facfae26b5654c9eff321f4cbc1a7"},{"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"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","baseScore":9.1,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","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's 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":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:23:20.102Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.6.120"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.12.64"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.18.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.19"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}