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 19738.0.0

medium Tenable Cloud Security Plugin ID 472137

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: ext4: don't zero the entire extent if
EXT4_EXT_DATA_PARTIAL_VALID1 When allocating initialized blocks from a large unwritten extent, or when
splitting an unwritten extent during end I/O and converting it to initialized, there is currently a
potential issue of stale data if the extent needs to be split in the middle. 0 A B N [UUUUUUUUUUUU] U:
unwritten extent [--DDDDDDDD--] D: valid data |<- ->| ----> this range needs to be initialized
ext4_split_extent() first try to split this extent at B with EXT4_EXT_DATA_ENTIRE_VALID1 and
EXT4_EXT_MAY_ZEROOUT flag set, but ext4_split_extent_at() failed to split this extent due to temporary
lack of space. It zeroout B to N and mark the entire extent from 0 to N as written. 0 A B N [WWWWWWWWWWWW]
W: written extent [SSDDDDDDDDZZ] Z: zeroed, S: stale data ext4_split_extent() then try to split this
extent at A with EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left a stale written
extent from 0 to A. 0 A B N [WW|WWWWWWWWWW] [SS|DDDDDDDDZZ] Fix this by pass EXT4_EXT_DATA_PARTIAL_VALID1
to ext4_split_extent_at() when splitting at B, don't convert the entire extent to written and left it as
unwritten after zeroing out B to N. The remaining work is just like the standard two-part split.
ext4_split_extent() will pass the EXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the
second time, allowing it to properly handle the split. If the split is successful, it will keep extent
from 0 to A as unwritten. (CVE-2026-45858)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19738.0.0 or later.

Plugin Details

Severity: Medium

ID: 472137

Version: Revision 1.2

Type: Local

Family: Google COS Security Checks

Published: 10/3/2026

Updated: 10/3/2026

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

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.75

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-2026-45858

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: 3/27/2026

Reference Information

CVE: CVE-2026-45858

Detections

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