{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72354","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-09T03:40:39.921Z","datePublished":"2026-08-15T05:55:56.163Z","dateUpdated":"2026-08-17T05:43:12.145Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T05:43:12.145Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: avoid stale runlist element dereference in MFT writeback\n\nntfs_write_mft_block() maps each $MFT record through the $MFT data\nrunlist. For sub-folio clusters it looks up a struct runlist_element under\nni->runlist.lock, drops the lock, and later uses rl->length and rl->vcn\nwhen choosing folio_sz.\n\nThat pointer is only borrowed from ni->runlist.rl. Concurrent $MFT\nallocation extension can merge a replacement runlist under the same lock,\nand ntfs_rl_realloc() can free the old backing array. If that happens\nbetween the lookup and the later folio_sz decision, writeback can\ndereference freed runlist storage.\n\nThe buggy scenario involves two paths, with each column showing the order\nwithin that path:\n\nMFT writeback path:               $MFT allocation extension:\n1. Look up rl under               1. Extend the $MFT data allocation.\n   ni->runlist.lock.              2. Publish a replacement runlist.\n2. Drop ni->runlist.lock.         3. Free the old runlist array.\n3. Read rl->length and rl->vcn\n   to choose folio_sz.\n\nCompute the remaining run length while ni->runlist.lock is still held, and\nuse that scalar after unlock. This preserves the existing folio sizing\ndecision without carrying a borrowed runlist_element across the lock\nboundary.\n\nValidation reproduced this kernel report:\nBUG: KASAN: slab-use-after-free in ntfs_mft_writepages+0x1c8d/0x1fb0\n\nCall Trace:\n <TASK>\n dump_stack_lvl+0x66/0xa0\n print_report+0xce/0x630\n ? ntfs_mft_writepages+0x1c8d/0x1fb0\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __virt_addr_valid+0x20d/0x410\n ? ntfs_mft_writepages+0x1c8d/0x1fb0\n kasan_report+0xe0/0x110\n ? ntfs_mft_writepages+0x1c8d/0x1fb0\n ntfs_mft_writepages+0x1c8d/0x1fb0\n ? __pfx_ntfs_mft_writepages+0x10/0x10\n ? __pfx___mutex_unlock_slowpath+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? iput+0x92/0xa80\n do_writepages+0x219/0x530\n ? __pfx_do_writepages+0x10/0x10\n __writeback_single_inode+0x117/0xf50\n ? do_raw_spin_lock+0x130/0x270\n ? __pfx_do_raw_spin_lock+0x10/0x10\n ? __pfx___writeback_single_inode+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n writeback_sb_inodes+0x65b/0x1810\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? lock_acquire+0x2b8/0x2f0\n ? __pfx_writeback_sb_inodes+0x10/0x10\n ? lock_release+0x1e0/0x280\n ? _raw_spin_unlock+0x23/0x40\n ? move_expired_inodes+0x2b8/0x850\n __writeback_inodes_wb+0xf4/0x270\n ? __pfx___writeback_inodes_wb+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? queue_io+0x2e4/0x410\n wb_writeback+0x666/0x880\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __pfx_wb_writeback+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? get_nr_dirty_inodes+0x1c/0x170\n wb_workfn+0x75e/0xbb0\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? _raw_spin_unlock_irqrestore+0x27/0x60\n ? __pfx_wb_workfn+0x10/0x10\n ? __pfx_debug_object_deactivate+0x10/0x10\n ? lock_acquire+0x2b8/0x2f0\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? lock_release+0x1e0/0x280\n process_one_work+0x8d0/0x1870\n ? __pfx_process_one_work+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n worker_thread+0x575/0xf80\n ? __pfx_worker_thread+0x10/0x10\n kthread+0x2e7/0x3c0\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x576/0x810\n ? __pfx_ret_from_fork+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __switch_to+0x57e/0xe10\n ? __switch_to_asm+0x33/0x70\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n </TASK>\n\nAllocated by task 970:\n kasan_save_stack+0x33/0x60\n kasan_save_track+0x14/0x30\n __kasan_kmalloc+0xaa/0xb0\n __kvmalloc_node_noprof+0x353/0x920\n ntfs_rl_realloc+0x3c/0x80\n ntfs_runlists_merge+0x1212/0x3010\n ntfs_mft_data_extend_allocation_nolock+0x3e0/0x1f40\n ntfs_mft_record_alloc+0x1ab4/0x4f10\n __ntfs_create+0x680/0x2e50\n ntfs_create+0x1e6/0x3a0\n path_openat+0x2b55/0x3c10\n do_file_open+0x1f4/0x460\n do_sys_openat2+0xde/0x170\n __x64_sys_openat+0x122/0x1e0\n do_syscall_64+0x115/0x6a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nFreed by task 1294:\n kasan_save_\n---truncated---"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - Remote clients can reach ntfs_create/ntfs_mft_record_alloc via ksmbd, NFS, or Samba on an rw-mounted NTFS export, racing the kernel $MFT writeback worker without local shell access.\nAC:L - The attacker controls concurrent file creation that extends $MFT allocation while dirty MFT folios write back; the fix commit documents a reproducible KASAN UAF from this attacker-influenced race.\nPR:L - Only filesystem write permission on an rw-mounted NTFS volume is required (local unprivileged user or authenticated network share client), not real root in the initial mount namespace.\nUI:N - No victim interaction is needed; the attacker triggers metadata writes and relies on automatic writeback once $MFT pages are dirty.\nS:U - Impact is confined to kernel NTFS/$MFT writeback on the host; it does not cross VM, hypervisor, or IOMMU security boundaries.\nC:H - Slab use-after-free of runlist_element fields permits reading freed or attacker-influenced kernel memory, matching UAF arbitrary-read exploitation potential.\nI:H - Freed runlist contents control folio_sz and bio sizing for $MFT writeback, enabling misdirected kernel writes and standard UAF-based arbitrary write primitives.\nA:H - Reproduced as KASAN slab-use-after-free in ntfs_mft_writepages; stale runlist dereference can oops or panic the kernel during the race."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs/mft.c"],"versions":[{"version":"115380f9a2f9675c7924563cbba70d40cae8fb81","lessThan":"9a2e36963a3fc52401586657d34e3f1c5a01ea56","status":"affected","versionType":"git"},{"version":"115380f9a2f9675c7924563cbba70d40cae8fb81","lessThan":"81fe702ff1760da32bcd3ef4494b2a33dbeced72","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs/mft.c"],"versions":[{"version":"7.1","status":"affected"},{"version":"0","lessThan":"7.1","status":"unaffected","versionType":"semver"},{"version":"7.1.5","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/9a2e36963a3fc52401586657d34e3f1c5a01ea56"},{"url":"https://git.kernel.org/stable/c/81fe702ff1760da32bcd3ef4494b2a33dbeced72"}],"title":"ntfs: avoid stale runlist element dereference in MFT writeback","x_generator":{"engine":"bippy-1.2.0"}}}}