tracing/user_events: Clear copied tracing state before fork duplication (CVE-2026-89750) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89750

tracing/user_events: Clear copied tracing state before fork duplication

Answer in brief

CVE-2026-89750 records a Unknown severity vulnerability in tracing/user_events: Clear copied tracing state before fork duplication. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=7235759084a4f8524a46bd2638885ff3b34ce279 <63b39e49a4c9d68e010e96b26fc7374f0864f2b1 \|\| >=7235759084a4f8524a46bd2638885ff3b34ce279 <25a0758cf6bdbfddac2be71124c9bd0692f4b0b1 \|\| >=7235759084a4f8524a46bd2638885ff3b34ce279 <b799f67119aff179719a0b1e12441ebbdaaf62f9 \|\| >=7235759084a4f8524a46bd2638885ff3b34ce279 <390f6bd8583d177029d9df4bea6667509e55a765	63b39e49a4c9d68e010e96b26fc7374f0864f2b1, 25a0758cf6bdbfddac2be71124c9bd0692f4b0b1, b799f67119aff179719a0b1e12441ebbdaaf62f9, 390f6bd8583d177029d9df4bea6667509e55a765
Linux/Linuxgeneric	6.4	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 63b39e49a4c9d68e010e96b26fc7374f0864f2b1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source 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+0x77/0x7f Allocated by task 44: __kasan_kmalloc+0x8f/0xa0 __kmalloc_cache_noprof+0x180/0x3a0 user_event_mm_alloc+0x3c/0x1f0 current_user_event_mm+0x88/0x1d0 Freed by task 42: __kasan_slab_free+0x43/0x70 kfree+0x13a/0x390 process_one_work+0x696/0xf90 worker_thread+0x420/0xba0 The fix simply clears the copied pointer before any possible failure. In case of failure, the child then has nothing to free.

Quoted source text, attributed separately from HOL analysis.