{"id":"CVE-2026-99171","state":"PUBLISHED","title":"ntfs3: free the sbi after a grace period","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: free the sbi after a grace period\n\nIf the \"nocase\" mount option ntfs3 uses custom hash and dentry compare\nfunctions. Both access ntfs3 superblock private information in rcu\npathwalk. ntfs_put_super() and ntfs3_kill_sb() drop the info without any\nrcu delay. A lookup that's still inside the filesystem when the last\nreference to the mount is dropped causes a UAF. With a pathwalk held up\nin ntfs_d_hash() while the last reference to the mount goes away:\n\n  BUG: KASAN: slab-use-after-free in ntfs_nls_to_utf16+0x752/0x940\n  Read of size 8 at addr ff1100010453c850 by task walker/99\n  Call Trace:\n   <TASK>\n   ntfs_nls_to_utf16+0x752/0x940\n   ntfs_d_hash+0x22b/0x500\n   link_path_walk+0x11ad/0x1d30\n   path_lookupat+0x63/0xb00\n   filename_lookup+0x1f1/0x5b0\n   vfs_statx+0xd7/0x3b0\n  [...]\n  Allocated by task 95:\n   __kmalloc_cache_noprof+0x249/0x560\n   ntfs_init_fs_context+0x2db/0x5a0\n   alloc_fs_context+0x52e/0xc70\n  [...]\n  Freed by task 98:\n   kfree+0x1db/0x5b0\n   deactivate_locked_super+0x9c/0xf0\n   cleanup_mnt+0x9f/0x130\n   task_work_run+0x131/0x250\n\nThe bug is currently masked by the grace period in namespace_unlock()\nfor umount(2). Keep the necessary information until the filesystem\nprivate info is freed and free it with an rcu delay.\n\nntfs3_free_sbi() now runs from an rcu callback and drops the upcase\ntable via ntfs_put_shared(). So switch s_shared_lock over to\nspin_lock_bh(). Otherwise the callback can deadlock against a task\nholding the lock on the same cpu.","publishedAt":"2026-10-28T10:35:26.598Z","updatedAt":"2026-10-30T12:42:35.809Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"c39150784a801dbbfaf4fbfa284cb610552a5039","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"36e6753daf9bb64563dcb5a3bb22f7699d973fa2","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"c8b1a4840467930e01f1a9374d991d7a8a2896c1","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"7abecef26a9be8f9de70659a3092250461a52072","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"c01b091b06412d3b1b53d8c2925f6de586c8a2fc","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs3/ntfs_fs.h","fs/ntfs3/super.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs3/ntfs_fs.h","fs/ntfs3/super.c"]}],"references":["https://git.kernel.org/stable/c/c39150784a801dbbfaf4fbfa284cb610552a5039","https://git.kernel.org/stable/c/36e6753daf9bb64563dcb5a3bb22f7699d973fa2","https://git.kernel.org/stable/c/c8b1a4840467930e01f1a9374d991d7a8a2896c1","https://git.kernel.org/stable/c/7abecef26a9be8f9de70659a3092250461a52072","https://git.kernel.org/stable/c/c01b091b06412d3b1b53d8c2925f6de586c8a2fc"],"weaknesses":[],"ingestedAt":"2026-10-30T13:02:04.640Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99171.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99171","state":"PUBLISHED","datePublished":"2026-10-28T10:35:26.598Z","dateUpdated":"2026-10-30T12:42:35.809Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.399Z"},"containers":{"cna":{"title":"ntfs3: free the sbi after a grace period","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: free the sbi after a grace period\n\nIf the \"nocase\" mount option ntfs3 uses custom hash and dentry compare\nfunctions. Both access ntfs3 superblock private information in rcu\npathwalk. ntfs_put_super() and ntfs3_kill_sb() drop the info without any\nrcu delay. A lookup that's still inside the filesystem when the last\nreference to the mount is dropped causes a UAF. With a pathwalk held up\nin ntfs_d_hash() while the last reference to the mount goes away:\n\n  BUG: KASAN: slab-use-after-free in ntfs_nls_to_utf16+0x752/0x940\n  Read of size 8 at addr ff1100010453c850 by task walker/99\n  Call Trace:\n   <TASK>\n   ntfs_nls_to_utf16+0x752/0x940\n   ntfs_d_hash+0x22b/0x500\n   link_path_walk+0x11ad/0x1d30\n   path_lookupat+0x63/0xb00\n   filename_lookup+0x1f1/0x5b0\n   vfs_statx+0xd7/0x3b0\n  [...]\n  Allocated by task 95:\n   __kmalloc_cache_noprof+0x249/0x560\n   ntfs_init_fs_context+0x2db/0x5a0\n   alloc_fs_context+0x52e/0xc70\n  [...]\n  Freed by task 98:\n   kfree+0x1db/0x5b0\n   deactivate_locked_super+0x9c/0xf0\n   cleanup_mnt+0x9f/0x130\n   task_work_run+0x131/0x250\n\nThe bug is currently masked by the grace period in namespace_unlock()\nfor umount(2). Keep the necessary information until the filesystem\nprivate info is freed and free it with an rcu delay.\n\nntfs3_free_sbi() now runs from an rcu callback and drops the upcase\ntable via ntfs_put_shared(). So switch s_shared_lock over to\nspin_lock_bh(). Otherwise the callback can deadlock against a task\nholding the lock on the same cpu."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"c39150784a801dbbfaf4fbfa284cb610552a5039","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"36e6753daf9bb64563dcb5a3bb22f7699d973fa2","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"c8b1a4840467930e01f1a9374d991d7a8a2896c1","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"7abecef26a9be8f9de70659a3092250461a52072","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","status":"affected","lessThan":"c01b091b06412d3b1b53d8c2925f6de586c8a2fc","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs3/ntfs_fs.h","fs/ntfs3/super.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs3/ntfs_fs.h","fs/ntfs3/super.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c39150784a801dbbfaf4fbfa284cb610552a5039"},{"url":"https://git.kernel.org/stable/c/36e6753daf9bb64563dcb5a3bb22f7699d973fa2"},{"url":"https://git.kernel.org/stable/c/c8b1a4840467930e01f1a9374d991d7a8a2896c1"},{"url":"https://git.kernel.org/stable/c/7abecef26a9be8f9de70659a3092250461a52072"},{"url":"https://git.kernel.org/stable/c/c01b091b06412d3b1b53d8c2925f6de586c8a2fc"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:42:35.809Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.161"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.12.115"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.18.59"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.2.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}