Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-98861— fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching()

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.

在 Linux 内核中，以下漏洞已得到修复： fprobe：使用 并检查 和 （由 BPF kprobe-multi 使用）依赖标准的 RCU 宽限期（ 和 ）来等待所有正在执行的 fprobe 处理程序完成，之后才释放 fprobe 对象。 然而，如果 fprobe 处理程序在 RCU 未进行监控的情况下执行（例如在空闲循环中，或在 扩展的静默状态下），标准 RCU 不会跟踪被禁用抢占的代码段。因此， 不会等待这些执行完成，这可能导致在注销后立即释放 fprobe 时出现释放后使用（use-after-free）

AI Predicted 7.8 Difficulty: Moderate EPSS 0.17% · P6

Affected Version Matrix 11

VendorProduct Version RangeStatus
Linux Linux 56b4cfcf1518245493c60fd39c56978f508f1816< a85d0f00671b4d4527317c10ba018680f7d8d673 affected
657b594b2084b39a4bc6d8493aa2140cb00cea49< dd4a0d4993633b45470abf6da4ea0ca563402245 affected
657b594b2084b39a4bc6d8493aa2140cb00cea49< e0a6249190402a28f1e2925a81acf573157d55ef affected
a4f6a9005ed6cfd360ef2520430927f05f92ffb0 affected
6.18.34< 6.18.56 affected
7.0.11< 7.1 affected
7.1 affected
< 7.1 unaffected
… +3 more rows
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-98861

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching() unregister_fprobe() and unregister_fprobe_async() (used by BPF kprobe-multi) rely on standard RCU grace periods (synchronize_rcu() and call_rcu()) to wait until in-flight fprobe handlers complete before freeing the fprobe. However, if an fprobe handler executes while RCU is not watching (such as in the idle loop or nohz_full extended quiescent states), standard RCU does not track preemption-disabled sections. Consequently, synchronize_rcu() does not wait for those executions, which can lead to a use-after-free if the fprobe is freed immediately after unregistration. Ensure handlers exit early when !rcu_is_watching(). Furthermore, fprobe_fgraph_entry() and fprobe_ftrace_entry() previously used guard(rcu)() and rcu_read_lock(), which invoke lockdep on every hit under CONFIG_PROVE_LOCKING. This adds overhead and can cause lockdep recursion if probed functions interact with lockdep. Since rhltable_lookup() and rhl_for_each_entry_rcu() use rcu_dereference_all_check() (which checks rcu_read_lock_any_held()), holding preemption disabled via rcu_read_lock_sched_notrace() is fully valid and sufficient so long as rcu_is_watching() is true. Define and use guard(rcu_sched_notrace)() across fprobe_ftrace_entry(), fprobe_fgraph_entry(), and fprobe_return(). This eliminates fast-path rcu_read_lock() and lockdep overhead while guaranteeing safe grace period synchronization.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 56b4cfcf1518245493c60fd39c56978f508f1816 ~ a85d0f00671b4d4527317c10ba018680f7d8d673 -
Linux Linux 7.1 -

II. Public POCs for CVE-2026-98861

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-98861

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-98861 (2)

Same Patch Batch · Linux · 2026-10-18 · 435 CVEs total

CVE-2026-98719 KVM: SEV: Nullify "have run CPUs" mask pointer when freeing it
CVE-2026-98732 Bluetooth: btintel: fix buffer over-read in btintel_hw_error()
CVE-2026-98731 Bluetooth: btintel_pcie: fix plen overflow in btintel_pcie_recv_frame()
CVE-2026-98730 Bluetooth: btintel_pcie: reject oversized TX packets in send_frame()
CVE-2026-98729 x86/mm: Don't apply va_align to hugetlb mappings on AMD F15h
CVE-2026-98728 tpm: fix off-by-four bounds check in tpm2_get_random()
CVE-2026-98727 nvme-multipath: set BLK_FEAT_ZONED only after the zone info is known
CVE-2026-98726 nvme-multipath: fix underflow in ANA log bounds checks
CVE-2026-98725 nvmet-auth: fix out-of-bounds write in nvmet_auth_challenge()
CVE-2026-98724 nvmet: pci-epf: reject too-short SGL segments
CVE-2026-98723 nvmet: copy the hostid into the ctrl before creating PR pc_refs
CVE-2026-98722 mtd: block2mtd: Fix divide error when erase_size is zero
CVE-2026-98721 mtd: rawnand: cadence: Initialize IRQ state before requesting IRQ
CVE-2026-98720 KVM: nVMX: Force MSR bitmap refresh if runtime eVMCS controls are modified
CVE-2026-98707 wifi: mac80211: shut down RX BA session timer on teardown
CVE-2026-98711 wifi: cw1200: fix TX padding OOB read leaking heap data to device
CVE-2026-98710 wifi: iwlegacy: 3945: free EEPROM data on remove
CVE-2026-98709 wifi: mac80211: count only matching reservations in reserved switch
CVE-2026-98712 KVM: arm64: vgic: Take a refcount on IRQs referenced by last_lr_irq
CVE-2026-98708 wifi: mac80211: keep paired old chanctx alive

Showing top 20 of 435 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-98861

No comments yet

Leave a comment