{"id":"CVE-2026-72381","summary":"ksmbd: fix use-after-free of fp-\u003eowner.name in durable handle owner check","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free of fp-\u003eowner.name in durable handle owner check\n\nTwo concurrent SMB2 durable reconnects (DH2C/DHnC) on the same\npersistent_id race the fp-\u003eowner.name compare-read in\nksmbd_vfs_compare_durable_owner() against the kfree() in\nksmbd_reopen_durable_fd()'s reopen-success path. fp-\u003eowner.name is a\nstandalone kstrdup() buffer whose lifetime is independent of the fp\nrefcount, and the two sites share no lock: the compare reads the buffer\nwhile the reopen frees it, so the strcmp() can dereference freed memory.\n\nCommit 7ce4fc40018d (\"ksmbd: fix durable reconnect double-bind race in\nksmbd_reopen_durable_fd\") made the fp-\u003econn claim atomic under\nglobal_ft.lock (closing the owner.name double-free and the ksmbd_file\nwrite-UAF), but the compare-read versus reopen-free pair was left\nunserialized.\n\n  BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80\n  Read of size 1 by task kworker\n    strcmp\n    ksmbd_vfs_compare_durable_owner\n    smb2_check_durable_oplock\n    smb2_open\n  Freed by task kworker:\n    kfree\n    ksmbd_reopen_durable_fd\n    smb2_open\n  Allocated by task kworker:\n    kstrdup\n    session_fd_check\n    smb2_session_logoff\n  The buggy address belongs to the cache kmalloc-8\n\nSerialize both sides of the race with fp-\u003ef_lock.  The global durable\nfile-table lock still protects the durable reconnect claim, but\nfp-\u003eowner.name is per-open state and does not need to block unrelated\ndurable table lookups or reconnects.  The teardown is left at its\nexisting location after the reopen-success point so that an __open_id()\nrollback still retains owner.name for a later legitimate reconnect to\nverify.","modified":"2026-10-08T02:51:47.690184094Z","published":"2026-08-15T05:56:13.477Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72381.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/38637163501fd9e2f684b8cd275d0db5d79f37c6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5a5ac2852cd326529d02f778bc1aa6184701f4d7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/93d4d46bf9d442a12ea87278049ec416962c627f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ed98719be41389d416953b8ef9f07a07dfea6b2b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fb978d72052704c6b06c6b0f129fcd60b77169f5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72381.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72381"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"712cdf917e77a6444ce3836874829d770db20ee6"},{"fixed":"fb978d72052704c6b06c6b0f129fcd60b77169f5"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d"},{"fixed":"93d4d46bf9d442a12ea87278049ec416962c627f"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"00ce8d6789dae72d042a4522264964c72891ca37"},{"fixed":"5a5ac2852cd326529d02f778bc1aa6184701f4d7"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"49110a8ce654bbe56bef7c5e44cce31f4b102b8a"},{"fixed":"ed98719be41389d416953b8ef9f07a07dfea6b2b"},{"fixed":"38637163501fd9e2f684b8cd275d0db5d79f37c6"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.6.142"},{"fixed":"6.6.145"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.12.92"},{"fixed":"6.12.97"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.18.25"},{"fixed":"6.18.40"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"7.0.2"},{"fixed":"7.1"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c908c853f304a4969b5aa10eba0b50350cc65b80"}]}],"versions":["v6.6.144","v6.6.143","v6.6.142","v6.12.96","v6.12.95","v6.12.94","v6.12.93","v6.12.92","v6.18.39","v6.18.38","v6.18.37","v6.18.36","v6.18.35","v6.18.34","v6.18.33","v6.18.32","v6.18.31","v6.18.30","v6.18.29","v6.18.28","v6.18.27","v6.18.26","v6.18.25","v7.0.14","v7.0.13","v7.0.12","v7.0.11","v7.0.10","v7.0.9","v7.0.8","v7.0.7","v7.0.6","v7.0.5","v7.0.4","v7.0.3","v7.0.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72381.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.97"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.40"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72381.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}