CVE-2024-43870

MEDIUM EPSS 11.3%
Published Aug 21, 20241y ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
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Published Aug 21, 2024 1y ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: perf: Fix event leak upon exit When a task is scheduled out, pending sigtrap deliveries are deferred to the target task upon resume to userspace via task_work. However failures while adding an event's callback to the task_work engine are ignored. And since the last call for events exit happen after task work is eventually closed, there is a small window during which pending sigtrap can be queued though ignored, leaking the event refcount addition such as in the following scenario: TASK A ----- do_exit() exit_task_work(tsk); <IRQ> perf_event_overflow() event->pending_sigtrap = pending_id; irq_work_queue(&event->pending_irq); </IRQ> =========> PREEMPTION: TASK A -> TASK B event_sched_out() event->pending_sigtrap = 0; atomic_long_inc_not_zero(&event->refcount) // FAILS: task work has exited task_work_add(&event->pending_task) [...] <IRQ WORK> perf_pending_irq() // early return: event->oncpu = -1 </IRQ WORK> [...] =========> TASK B -> TASK A perf_event_exit_task(tsk) perf_event_exit_event() free_event() WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1) // leak event due to unexpected refcount == 2 As a result the event is never released while the task exits. Fix this with appropriate task_work_add()'s error handling.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
11.3% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-401

Affected Products 7

VendorProductVersionRange
linuxlinux_kernel*≥5.15.84  –  <5.15.165
linuxlinux_kernel*≥6.0.14  –  <6.1
linuxlinux_kernel*≥6.1.1  –  <6.1.103
linuxlinux_kernel*≥6.2  –  <6.6.44
linuxlinux_kernel*≥6.7  –  <6.10.3
linuxlinux_kernel6.1any
linuxlinux_kernel6.1any

References 6

  • git.kernel.org https://git.kernel.org/stable/c/05d3fd599594abf79aad4484bccb2b26e1cb0b51
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2fd5ad3f310de22836cdacae919dd99d758a1f1b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3d7a63352a93bdb8a1cdf29606bf617d3ac1c22a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/67fad724f1b568b356c1065d50df46e6b30eb2f7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/70882d7fa74f0731492a0d493e8515a4f7131831
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/05d3fd599594abf79aad4484bccb2b26e1cb0b51
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2fd5ad3f310de22836cdacae919dd99d758a1f1b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3d7a63352a93bdb8a1cdf29606bf617d3ac1c22a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/67fad724f1b568b356c1065d50df46e6b30eb2f7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/70882d7fa74f0731492a0d493e8515a4f7131831
    Patch