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Expired Pointer Dereference Affecting kernel-debug-modules-internal package, versions *

Severity

 Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.13% (4th percentile)

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  • Snyk IDSNYK-CENTOS8-KERNELDEBUGMODULESINTERNAL-19031354
  • published21 Aug 2026
  • disclosed15 Aug 2026
Report a new vulnerability Found a mistake?

Introduced: 15 Aug 2026

NewCVE-2026-74481  (opens in a new tab)
CWE-825  (opens in a new tab)

How to fix?

There is no fixed version for Centos:8 kernel-debug-modules-internal.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules-internal package and not the kernel-debug-modules-internal package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

mm/page_reporting: use system_freezable_wq to fix UAF during suspend

During PM freeze (e.g. S3 suspend or S4 hibernation), device drivers like virtio_balloon reset their underlying virtio devices and delete their virtqueues via vdev->config->del_vqs().

However, page reporting work (page_reporting_process) was scheduled on the global system_wq. Because system_wq lacks the WQ_FREEZABLE flag, the PM freezer skips it, leaving page_reporting_process active during suspend.

If pages are freed into the buddy allocator while suspending (for example, when core MM invokes the balloon shrinker during S4 hibernation image saving), page reporting triggers virtballoon_free_page_report() on deleted virtqueues, resulting in a Use-After-Free / General Protection Fault:

[  196.795226] general protection fault, probably for non-canonical address 0xaa1436fe70dae6df: 0000 [#1] SMP NOPTI
[  196.825967] Workqueue: events page_reporting_process
[  196.831038] RIP: 0010:virtqueue_add_split+0x233/0x4c0 [virtio_ring]
[  196.927073] virtballoon_free_page_report+0x3a/0xe0 [virtio_balloon]
[  196.946943] page_reporting_process+0x370/0x4f0

Fix this by switching page reporting work to system_freezable_wq. This ensures that the PM freezer pauses page_reporting_process before device drivers destroy their reporting virtqueues. Because the reporting worker is frozen, memory reclamation/freeing (e.g. via shrinker execution) can safely return pages to MM during freeze without triggering unfrozen reporting work on deleted virtqueues.

This aligns with the driver's existing design. The comment in virtballoon_freeze() states: /* * The workqueue is already frozen by the PM core before this * function is called. */

Testing: I have verified these fixes using Google’s virtualization infrastructure by running continuous suspend/resume iterations (40+ cycles) while churning memory using stress-ng (stress-ng --vm 4 --vm-bytes 60% --timeout 1) to constantly create free pages for the buddy allocator. We also set the page_reporting_order parameter to 0 to make the page reporting worker highly sensitive, forcing it to pick up any 4K free pages. This confirmed that the UAF crashes are no longer reproducible.

CVSS Base Scores

version 3.1