{"schema":"threatline.record/2","record":{"id":"CVE-2026-99171","aliases":[],"summary":"ntfs3: free the sbi after a grace period","details":"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.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99171","source_modified_at":"2026-10-28T10:35:26.598Z","fetched_at":"2026-10-28T15:55:58.673066Z","product":"Linux","vendor":"Linux","versions":[{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","lessThan":"c8b1a4840467930e01f1a9374d991d7a8a2896c1","status":"affected","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","lessThan":"7abecef26a9be8f9de70659a3092250461a52072","status":"affected","versionType":"git"},{"version":"a3a956c78efaa202b1d75190136671cf6e87bfbe","lessThan":"c01b091b06412d3b1b53d8c2925f6de586c8a2fc","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99171","source_modified_at":"2026-10-28T10:35:26.598Z","fetched_at":"2026-10-28T15:55:58.673066Z","product":"Linux","vendor":"Linux","versions":[{"version":"6.2","status":"affected"},{"version":"0","lessThan":"6.2","status":"unaffected","versionType":"semver"},{"version":"6.18.59","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.13","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99171","source_modified_at":"2026-10-28T10:35:26.598Z","fetched_at":"2026-10-28T15:55:58.673066Z","package":{"name":"Linux","ecosystem":null},"version":"7abecef26a9be8f9de70659a3092250461a52072","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":null,"percentile":null,"score_date":null},"published_at":"2026-10-28T10:35:26.598Z","modified_at":"2026-10-28T10:35:26.598Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-99171","fetched_at":"2026-10-28T15:55:58.673066Z","source_modified_at":"2026-10-28T10:35:26.598Z"}],"sources":["CVE List"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/c8b1a4840467930e01f1a9374d991d7a8a2896c1"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/7abecef26a9be8f9de70659a3092250461a52072"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/c01b091b06412d3b1b53d8c2925f6de586c8a2fc"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-28T10:35:26.598Z","content_hash":"63780ace339c1644981b0b630a73362d698f2e6e64cd482b07e86828d17207e0"}}