Google: sys-kernel/csql-kernel-6_1, sys-kernel/csql-kernel-6_6, sys-kernel/lakitu-kernel-6_1, sys-kernel/lakitu-kernel-6_6, sys-kernel/lakitu-nc-kernel-6_6, sys-kernel/lakitu-vgpu-kernel-6_6, sys-kernel/tpusev-kernel-6_6: security update to 18613.613.5

high Tenable Cloud Security Plugin ID 467179

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: fix e4b bitmap inconsistency
reports A bitmap inconsistency issue was observed during stress tests under mixed huge-page workloads.
Ext4 reported multiple e4b bitmap check failures like: ext4_mb_complex_scan_group:2508: group 350, 8179
free clusters as per group info. But got 8192 blocks Analysis and experimentation confirmed that the issue
is caused by a race condition between page migration and bitmap modification. Although this timing window
is extremely narrow, it is still hit in practice: folio_lock ext4_mb_load_buddy __migrate_folio check ref
count folio_mc_copy __filemap_get_folio folio_try_get(folio) ...... mb_mark_used ext4_mb_unload_buddy
__folio_migrate_mapping folio_ref_freeze folio_unlock The root cause of this issue is that the fast path
of load_buddy only increments the folio's reference count, which is insufficient to prevent concurrent
folio migration. We observed that the folio migration process acquires the folio lock. Therefore, we can
determine whether to take the fast path in load_buddy by checking the lock status. If the folio is locked,
we opt for the slow path (which acquires the lock) to close this concurrency window. Additionally, this
change addresses the following issues: When the DOUBLE_CHECK macro is enabled to inspect bitmap-related
issues, the following error may be triggered: corruption in group 324 at byte 784(6272): f in copy != ff
on disk/prealloc Analysis reveals that this is a false positive. There is a specific race window where the
bitmap and the group descriptor become momentarily inconsistent, leading to this error report:
ext4_mb_load_buddy ext4_mb_load_buddy __filemap_get_folio(create|lock) folio_lock ext4_mb_init_cache
folio_mark_uptodate __filemap_get_folio(no lock) ...... mb_mark_used mb_mark_used_double mb_cmp_bitmaps
mb_set_bits(e4b->bd_bitmap) folio_unlock The original logic assumed that since mb_cmp_bitmaps is called
when the bitmap is newly loaded from disk, the folio lock would be sufficient to prevent concurrent
access. However, this overlooks a specific race condition: if another process attempts to load buddy and
finds the folio is already in an uptodate state, it will immediately begin using it without holding folio
lock. (CVE-2026-45942)

Solution

Update the sys-kernel/csql-kernel-6_1 library and its related packages to version 18613.613.5 or later.

Plugin Details

Severity: High

ID: 467179

Version: Revision 1.1

Type: Local

Family: Google COS Security Checks

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.36

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-2026-45942

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: 3/27/2026

Reference Information

CVE: CVE-2026-45942

Detections

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