{"id":"CVE-2026-89600","title":"fanotify: fix use-after-free of file range info","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nfanotify: fix use-after-free of file range info\n\nfsnotify_pre_content() builds its file_range on the triggering task's\nstack. fanotify_alloc_perm_event() saves a pointe…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 < 66aa9a9e6481bfa512ee5b6380eaaec455a954d2","Linux >= 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 < b8f73b163b646bc56d4dce9c697a578e333f4894","Linux >= 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 < d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851","Linux 6.14"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:49:32.566Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89600","references":[{"url":"https://git.kernel.org/stable/c/66aa9a9e6481bfa512ee5b6380eaaec455a954d2"},{"url":"https://git.kernel.org/stable/c/b8f73b163b646bc56d4dce9c697a578e333f4894"},{"url":"https://git.kernel.org/stable/c/d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89600.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89600"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532299"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89600"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89600"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89600.mbox"}],"tags":["cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00124,"epssPercentile":0.02096,"scores":{"cna":7.8,"vendor":5.5},"ingestedAt":"2026-09-14T15:23:07.474Z","slug":"CVE-2026-89600","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nfanotify: fix use-after-free of file range info\n\nfsnotify_pre_content() builds its file_range on the triggering task's\nstack. fanotify_alloc_perm_event() saves a pointer to range.pos in the\nheap-allocated permission event so copy_range_info_to_user() can report\nthe offset later.\n\nThe event reader can set the event state to FAN_EVENT_REPORTED and then\nsleep while preparing the file descriptor. If a signal interrupts the\ntriggering task at that point, fanotify_get_response() changes the state\nto FAN_EVENT_CANCELED and returns. This unwinds the file_range stack\nframe while the reader still owns the event. The reader then dereferences\npevent->ppos and copies the stale stack value to userspace.\n\nKASAN reported:\n\n  BUG: KASAN: use-after-free in fanotify_read+0x293e/0x2970\n  Read of size 8 at addr ffff88811434fc50 by task fanotify_inotif/95\n  Call Trace:\n   fanotify_read+0x293e/0x2970\n   vfs_read+0x177/0xa20\n   ksys_read+0xf7/0x1c0\n   do_syscall_64+0xf9/0x540\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nStore the range position directly in the permission event and use\nFANOTIFY_NO_RANGE when range information is unavailable. The event remains\nalive until the reader finishes, so the reported offset no longer depends\non the triggering task's stack.\n\n## Affected\n\n- `Linux >= 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 < 66aa9a9e6481bfa512ee5b6380eaaec455a954d2`\n- `Linux >= 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 < b8f73b163b646bc56d4dce9c697a578e333f4894`\n- `Linux >= 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 < d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851`\n- `Linux 6.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89600.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224682,"id":"CVE-2026-89600","ts":1792401471226,"field":"cvss","old":"5.5","new":"7.8"},{"seq":224681,"id":"CVE-2026-89600","ts":1792401471226,"field":"severity","old":"medium","new":"high"},{"seq":208139,"id":"CVE-2026-89600","ts":1789922723401,"field":"cvss","old":"5.3","new":"5.5"},{"seq":202865,"id":"CVE-2026-89600","ts":1789403732724,"field":"cvss","old":"7.8","new":"5.3"},{"seq":202864,"id":"CVE-2026-89600","ts":1789403732724,"field":"severity","old":"high","new":"medium"},{"seq":197874,"id":"CVE-2026-89600","ts":1789384320766,"field":"cvss","old":"5.3","new":"7.8"},{"seq":197873,"id":"CVE-2026-89600","ts":1789384320766,"field":"severity","old":"medium","new":"high"},{"seq":183427,"id":"CVE-2026-89600","ts":1789356675325,"field":"cvss","old":"7.8","new":"5.3"},{"seq":183426,"id":"CVE-2026-89600","ts":1789356675325,"field":"severity","old":"high","new":"medium"},{"seq":153420,"id":"CVE-2026-89600","ts":1789285350441,"field":"cvss","old":null,"new":"7.8"},{"seq":153419,"id":"CVE-2026-89600","ts":1789285350441,"field":"severity","old":"none","new":"high"},{"seq":147420,"id":"CVE-2026-89600","ts":1789270210839,"field":"cvss","old":null,"new":"5.3"},{"seq":147419,"id":"CVE-2026-89600","ts":1789270210839,"field":"severity","old":"none","new":"medium"},{"seq":109170,"id":"CVE-2026-89600","ts":1789183730585,"field":"cvss","old":null,"new":"5.3"},{"seq":109169,"id":"CVE-2026-89600","ts":1789183730585,"field":"severity","old":"none","new":"medium"}]}