Google: sys-kernel/cchost-kernel-6_12, sys-kernel/csql-kernel-6_12, sys-kernel/lakitu-kernel-6_12, sys-kernel/lakitu-nc-kernel-6_12: security update to 19506.299.82

high Tenable Cloud Security Plugin ID 470200

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

- 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. (CVE-2026-74481)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19506.299.82 or later.

Plugin Details

Severity: High

ID: 470200

Version: Revision 1.6

Type: Local

Family: Google COS Security Checks

Published: 10/3/2026

Updated: 10/6/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.27

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2026-74481

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 8/11/2026

Reference Information

CVE: CVE-2026-74481

Detections

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