Google: sys-kernel/cchost-kernel-6_12, sys-kernel/cchost-kernel-6_18, sys-kernel/csql-kernel-6_12, sys-kernel/csql-kernel-6_18, sys-kernel/lakitu-kernel-6_12, sys-kernel/lakitu-kernel-6_18, sys-kernel/lakitu-nc-kernel-6_12, sys-kernel/lakitu-nc-kernel-6_18: security update to 19999.44.106

medium Tenable Cloud Security Plugin ID 475302

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/secretmem: properly account locked
pages secretmem accounts folios by treating memory as if it were mlock()'d and thus limited by the
RLIMIT_MEMLOCK limit. However the folios are unevictable and remain so until the inode is evicted,
eliminating usual mlock() semantics - mapping folios then unmapping them does not clear their unevictable
state, since it depends on AS_UNEVICTABLE, not PG_mlocked. A user can therefore easily work around the
RLIMIT_MEMLOCK limit - simply map then unmap and VmLck no longer counts the secretmem range. Worse, folios
are not accounted in the process's RSS, meaning the OOM killer won't know to kill the process. Repeatedly
mapping/unmapping (or forking) can then result in the consumption of all available system memory with
unevictable folios and cause system instability. A secretmem fd can be passed between processes and over
fork so a per-process limit simply does not make sense, so follow the precedent set by io_uring, perf,
skbuff, iommufd and xdp by tracking the number of locked pages in user_struct->locked_vm. Since the scope
tracked is actually inode lifetime, the RLIMIT_MEMLOCK applies per-user not per-process, so it doesn't
make sense to bypass for users with CAP_IPC_LOCK, therefore remove this bypass. There is simply no reason
to carry on marking the mapping as mlock()'d since it's misleading and the lifecycle is now correctly
handled, so remove this too. Note that secretmem does not support any form of truncation (including hole
punching) and the folios are unreclaimable, so the folios need only be accounted on fault and unaccounted
on inode destruction. __secretmem_account_pages() is more or less a duplicate of the code that io_uring
etc. use, but since this is a bug fix that needs backporting, defer any de-duplication efforts to a
follow-up. test_mlock_limit() asserts mlock_future_ok() on mmap(), however this has been removed, so
remove the test altogether for the fix. A new test will be sent separately for upstream. (CVE-2026-93243)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19999.44.106 or later.

Plugin Details

Severity: Medium

ID: 475302

Version: Revision 1.1

Type: Local

Family: Google COS Security Checks

Published: 10/16/2026

Updated: 10/16/2026

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.24

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

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

CVSS Score Source: CVE-2026-93243

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: 9/24/2026

Reference Information

CVE: CVE-2026-93243

Detections

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