Google: sys-kernel/cchost-kernel-6_12, sys-kernel/csql-kernel-6_6: security update to 19216.395.4

medium Tenable Cloud Security Plugin ID 472161

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/vmalloc: prevent RCU stalls in
kasan_release_vmalloc_node When CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during vmalloc
cleanup triggers expensive stack unwinding that acquires RCU read locks. Processing a large purge_list
without rescheduling can cause the task to hold CPU for extended periods (10+ seconds), leading to RCU
stalls and potential OOM conditions. The issue manifests in purge_vmap_node() ->
kasan_release_vmalloc_node() where iterating through hundreds or thousands of vmap_area entries and
freeing their associated shadow pages causes: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu:
Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l ... task:kworker/0:17 state:R running task
stack:28840 pid:6229 ... kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299
purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299 Each call to kasan_release_vmalloc() can free many pages,
and with page_owner tracking, each free triggers save_stack() which performs stack unwinding under RCU
read lock. Without yielding, this creates an unbounded RCU critical section. Add periodic cond_resched()
calls within the loop to allow: - RCU grace periods to complete - Other tasks to run - Scheduler to
preempt when needed The fix uses need_resched() for immediate response under load, with a batch count of
32 as a guaranteed upper bound to prevent worst-case stalls even under light load. (CVE-2026-43292)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19216.395.4 or later.

Plugin Details

Severity: Medium

ID: 472161

Version: Revision 1.1

Type: Local

Family: Google COS Security Checks

Published: 10/3/2026

Updated: 10/3/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.69

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

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

CVSS Score Source: CVE-2026-43292

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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: 4/7/2026

Reference Information

CVE: CVE-2026-43292

Detections

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