Google: sys-kernel/cchost-kernel-6_12, sys-kernel/csql-kernel-6_12, sys-kernel/csql-kernel-6_6, sys-kernel/lakitu-kernel-6_12, sys-kernel/lakitu-kernel-6_6, sys-kernel/lakitu-nc-kernel-6_12, sys-kernel/lakitu-nc-kernel-6_6, sys-kernel/lakitu-vgpu-kernel-6_6: security update to 19216.655.6

medium Tenable Self-Hosted Container Security Plugin ID 468794

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: validate donor file superblock
early in EXT4_IOC_MOVE_EXT Reject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not belong to
the same superblock as the original file. Currently, this validation is performed inside
ext4_move_extents() by mext_check_validity(), but only after lock_two_nondirectories() has already
acquired the inode locks. When the donor fd refers to a file on a different filesystem (e.g., overlayfs),
this late validation creates a circular lock dependency: CPU0 (overlayfs write) CPU1 (ext4 ioctl) ----
---- inode_lock(ovl_inode) mnt_want_write_file(filp) sb_start_write(ext4_sb) [sb_writers]
backing_file_write_iter() vfs_iter_write(real_file) file_start_write(real_file) sb_start_write(ext4_sb)
[blocked by freeze] lock_two_nondirectories() inode_lock(ovl_inode) [blocked] With a concurrent freeze
operation holding sb_writers write side, this forms a deadlock cycle: CPU0 waits for freeze to complete,
freeze waits for CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock. Since
EXT4_IOC_MOVE_EXT exchanges physical extents between two files, it fundamentally requires both files to
reside on the same ext4 filesystem. Moving the superblock check before any lock acquisition is both
semantically correct and eliminates the circular dependency by ensuring that cross-filesystem donor fds
are rejected before sb_writers or inode locks are taken. (CVE-2026-74307)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19216.655.6 or later.

Plugin Details

Severity: Medium

ID: 468794

Version: Revision 1.5

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: Low

Score: 3

Percentile: 23.59

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-2026-74307

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: 8/11/2026

Reference Information

CVE: CVE-2026-74307

Detections

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