fanotify: fix use-after-free of file range info
In the Linux kernel, the following vulnerability has been resolved: fanotify: fix use-after-free of file range info fsnotify_pre_content() builds its file_range on the triggering task's stack. fanotify_alloc_perm_event() saves a pointer to range.pos in the heap-allocated permission event so copy_range_info_to_user() can report the offset later. The event reader can set the event state to FAN_EVENT_REPORTED and then sleep while preparing the file descriptor. If a signal interrupts the triggering task at that point, fanotify_get_response() changes the state to FAN_EVENT_CANCELED and returns. This unwinds the file_range stack frame while the reader still owns the event. The reader then dereferences pevent->ppos and copies the stale stack value to userspace. KASAN reported: BUG: KASAN: use-after-free in fanotify_read+0x293e/0x2970 Read of size 8 at addr ffff88811434fc50 by task fanotify_inotif/95 Call Trace: fanotify_read+0x293e/0x2970 vfs_read+0x177/0xa20 ksys_read+0xf7/0x1c0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f Store the range position directly in the permission event and use FANOTIFY_NO_RANGE when range information is unavailable. The event remains alive until the reader finishes, so the reported offset no longer depends on the triggering task's stack.
CVE-2026-89600
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-89600
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "870499bc1d4dc04cba1f63dd5e7bc02b983e2458",
"lessThan": "66aa9a9e6481bfa512ee5b6380eaaec455a954d2",
"versionType": "git"
},
{
"status": "affected",
"version": "870499bc1d4dc04cba1f63dd5e7bc02b983e2458",
"lessThan": "b8f73b163b646bc56d4dce9c697a578e333f4894",
"versionType": "git"
},
{
"status": "affected",
"version": "870499bc1d4dc04cba1f63dd5e7bc02b983e2458",
"lessThan": "d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851",
"versionType": "git"
}
],
"programFiles": [
"fs/notify/fanotify/fanotify.c",
"fs/notify/fanotify/fanotify.h",
"fs/notify/fanotify/fanotify_user.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.14",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/notify/fanotify/fanotify.c",
"fs/notify/fanotify/fanotify.h",
"fs/notify/fanotify/fanotify_user.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89600
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #35108 · Revision 1
- Added to Heist Feed
- Publisher date