CVE-2026-89750

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

tracing/user_events: Clear copied tracing state before fork duplication

dup_task_struct() copies user_event_mm from the parent into the child,

without grabbing a reference to it. user_event_mm_dup() should

replace it, but it leaves that copied pointer unmodified if

user_event_mm_alloc() fails.

When the child exits, user_event_mm_remove() decrements a reference

the child never owned, which ultimately frees user_event_mm, while

the parent still as a stale pointer to it. This creates a UAF, which

KASAN reports as:

BUG: KASAN: slab-use-after-free in

current_user_event_mm+0x51/0x1d0 Write of size 4 at addr

ffff888005010d30 by task init/44

Call Trace:

<TASK>

kasan_report+0xce/0x100

kasan_check_range+0x10f/0x1e0

current_user_event_mm+0x51/0x1d0

user_events_ioctl+0x82e/0x15c0

__x64_sys_ioctl+0x139/0x1c0

do_syscall_64+0xce/0x450

entry_SYSCALL_64_after_hwframe+0x77/0x7

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References