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CVE-2026-89750— tracing/user_events: Clear copied tracing state before fork duplication

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于dup_task_struct()复制user_event_mm时未获取引用，且user_event_mm_alloc()失败时未清除复制的指针，导致子进程退出时错误释放user_event_mm，而父进程保留过期指针，造成释放后重用。

CVSS 7.8 · High EPSS 0.16% · P5

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux 7235759084a4f8524a46bd2638885ff3b34ce279< 33ce55b368b64d65941867add00e7f288cbb8234 affected
7235759084a4f8524a46bd2638885ff3b34ce279< 63b39e49a4c9d68e010e96b26fc7374f0864f2b1 affected
7235759084a4f8524a46bd2638885ff3b34ce279< 25a0758cf6bdbfddac2be71124c9bd0692f4b0b1 affected
7235759084a4f8524a46bd2638885ff3b34ce279< b799f67119aff179719a0b1e12441ebbdaaf62f9 affected
7235759084a4f8524a46bd2638885ff3b34ce279< 390f6bd8583d177029d9df4bea6667509e55a765 affected
6.4 affected
< 6.4 unaffected
6.6.157≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-89750

Vulnerability Information
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Vulnerability Title
tracing/user_events: Clear copied tracing state before fork duplication
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于dup_task_struct()复制user_event_mm时未获取引用，且user_event_mm_alloc()失败时未清除复制的指针，导致子进程退出时错误释放user_event_mm，而父进程保留过期指针，造成释放后重用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 7235759084a4f8524a46bd2638885ff3b34ce279 ~ 33ce55b368b64d65941867add00e7f288cbb8234 -
Linux Linux 6.4 -

II. Public POCs for CVE-2026-89750

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III. Intelligence Information for CVE-2026-89750

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Patches & Fixes for CVE-2026-89750 (4)

Other References for CVE-2026-89750 (1)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89669 9.8 CRITICAL nfsd: initialize copy-notify stateid before publishing it
CVE-2026-89536 9.8 CRITICAL SUNRPC: wait for in-flight client TLS handshake callback
CVE-2026-89533 9.8 CRITICAL svcrdma: Fix offset arithmetic in read_chunk_range
CVE-2026-81002 9.8 CRITICAL xdp: fix zero-copy frame layout
CVE-2026-89643 9.8 CRITICAL audit: avoid dropping live tree ref on fsnotify rule autoremove
CVE-2026-89526 9.8 CRITICAL svcrdma: Validate Read chunk positions before reconstruction
CVE-2026-89652 9.8 CRITICAL ceph: bound copied dentry name length in NFS export get_name
CVE-2026-89651 9.8 CRITICAL ceph: bound MDSCapAuth path and fs_name decode in handle_session()
CVE-2026-89653 9.8 CRITICAL ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode
CVE-2026-89654 9.8 CRITICAL ceph: fix UAF in check_new_map() on session freed during unlock
CVE-2026-89656 9.8 CRITICAL libceph: reject buckets with mismatched CRUSH ids
CVE-2026-89655 9.8 CRITICAL ceph: fix UAF in __kick_flushing_caps() on cf entry freed during unlock
CVE-2026-89712 9.8 CRITICAL NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock
CVE-2026-89658 9.8 CRITICAL NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup
CVE-2026-89660 9.8 CRITICAL NFSD: Prevent client use-after-free during admin state revocation
CVE-2026-89659 9.8 CRITICAL NFSD: Prevent client use-after-free during delegation revoke
CVE-2026-89708 9.8 CRITICAL nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown
CVE-2026-89662 9.8 CRITICAL NFSD: Prevent lock owner use-after-free during client teardown
CVE-2026-89689 9.8 CRITICAL nfsd: don't free session slots that are still in use
CVE-2026-89686 9.8 CRITICAL nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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