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CVE-2026-72071— tracing/user_events: Fix use-after-free in user_event_mm_dup()

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 6.4版本存在安全漏洞，该漏洞源于tracing/user_events中user_event_mm_dup()在fork()期间无锁遍历enabler列表，与user_event_enabler_destroy()存在竞争条件，可能导致释放后重用。

CVSS 7.8 · High EPSS 0.17% · P6

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux 7235759084a4f8524a46bd2638885ff3b34ce279< 25acb6711da6fa0382744fa92bd6d42a22c1ae68 affected
7235759084a4f8524a46bd2638885ff3b34ce279< 95400e7039cdfeb0b53652d521d766f1698cae95 affected
7235759084a4f8524a46bd2638885ff3b34ce279< b33ac2d39953efb12f598c0dae242c5f644ea669 affected
7235759084a4f8524a46bd2638885ff3b34ce279< 05b24f68f78ff3a1ef7f015f7327b35886b741f6 affected
7235759084a4f8524a46bd2638885ff3b34ce279< 50fd6dd755c6e48a38af2fa4621167eea56829c2 affected
6.4 affected
< 6.4 unaffected
6.6.148≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-72071

Vulnerability Information
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Vulnerability Title
tracing/user_events: Fix use-after-free in user_event_mm_dup()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: tracing/user_events: Fix use-after-free in user_event_mm_dup() user_event_mm_dup() walks the parent mm's enabler list locklessly under rcu_read_lock() during fork() (from copy_process()); it does not take event_mutex: rcu_read_lock(); list_for_each_entry_rcu(enabler, &old_mm->enablers, mm_enablers_link) enabler->event = user_event_get(orig->event); user_event_enabler_destroy() removes an enabler from that list with list_del_rcu() and then, without waiting for a grace period, drops the enabler's user_event reference with user_event_put() and frees the enabler with kfree(). A reader that loaded the enabler before the list_del_rcu() can still be walking it, which leads to two use-after-frees: - kfree(enabler) frees the enabler while that reader dereferences enabler->event. - user_event_put() may drop the last reference to the user_event, which is then freed (via delayed_destroy_user_event() on a work queue), while the same reader does user_event_get(orig->event) on it. Both are reachable by an unprivileged task that can open user_events_data: one multithreaded process that registers an enabler and then concurrently unregisters it and calls fork() triggers the race. KASAN reports a slab-use-after-free in user_event_mm_dup() during clone(), with a "refcount_t: addition on 0" warning when the user_event is freed. The enabler use-after-free was found first; the user_event one was reported by XIAO WU, and the earlier enabler-only fix did not address it. Defer both the user_event_put() and the kfree(enabler) to a work item queued with queue_rcu_work(), so they run only after an RCU grace period, once all readers walking the enabler list have finished. The put must run in process context because user_event_put() takes event_mutex on the last reference, so a work queue is used rather than call_rcu(). The now-unlocked put lets the locked argument of user_event_enabler_destroy() be removed; all callers are updated.
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 6.4版本存在安全漏洞，该漏洞源于tracing/user_events中user_event_mm_dup()在fork()期间无锁遍历enabler列表，与user_event_enabler_destroy()存在竞争条件，可能导致释放后重用。
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 ~ 25acb6711da6fa0382744fa92bd6d42a22c1ae68 -
Linux Linux 6.4 -

II. Public POCs for CVE-2026-72071

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III. Intelligence Information for CVE-2026-72071

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Patches & Fixes for CVE-2026-72071 (5)

Same Patch Batch · Linux · 2026-08-15 · 844 CVEs total

CVE-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-74279 10.0 CRITICAL crypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-74280 10.0 CRITICAL crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-72206 9.8 CRITICAL ntfs: validate index block header more strictly
CVE-2026-72065 9.8 CRITICAL net: mana: Validate the packet length reported by the NIC
CVE-2026-72129 9.8 CRITICAL nvmet-rdma: handle inline data with a nonzero offset
CVE-2026-72130 9.8 CRITICAL nvmet-auth: reject short AUTH_RECEIVE buffers
CVE-2026-72429 9.8 CRITICAL ipv6: ioam: fix type confusion of dst_entry
CVE-2026-72436 9.8 CRITICAL netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types
CVE-2026-72319 9.8 CRITICAL ipvs: ensure inner headers in ICMP errors are in headroom
CVE-2026-72317 9.8 CRITICAL SUNRPC: pin upper rpc_clnt across the TLS connect_worker
CVE-2026-74427 9.8 CRITICAL afs: Fix netns teardown to cancel the preallocation charger
CVE-2026-72137 9.8 CRITICAL xfrm: nat_keepalive: avoid double free on send error
CVE-2026-74428 9.8 CRITICAL rxrpc: Fix double unlock in rxrpc_recvmsg()
CVE-2026-74376 9.8 CRITICAL md/raid10: reset read_slot when reusing r10bio for discard

Showing top 20 of 844 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-72071

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