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 19506.299.3

high Tenable Self-Hosted Container Security Plugin ID 469828

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: netfs: Fix streaming write being
overwritten In order to avoid reading whilst writing, netfslib will allow "streaming writes" in which
dirty data is stored directly into folios without reading them first. Such folios are marked dirty but may
not be marked uptodate. If a folio is entirely written by a streaming write, uptodate will be set,
otherwise it will have a netfs_folio struct attached to ->private recording the dirty region. In the event
that a partially written streaming write page is to be overwritten entirely by a single write(),
netfs_perform_write() will try to copy over it, but doesn't discard the netfs_folio if it succeeds;
further, it doesn't correctly handle a partial copy that overwrites some of the dirty data. Fix this by
the following: (1) If the folio is successfully overwritten, free the netfs_folio struct before marking
the page uptodate. (2) If the copy to the folio partially fails, but short of the dirty data, just ignore
the copy. (3) If the copy partially fails and overwrites some of the dirty data, accept the copy, update
the netfs_folio struct to record the new data. If the folio is now filled, free the netfs_folio and set
uptodate, otherwise return a partial write. Found with: fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
/xfstest.test/junk --replay-ops=junk.fsxops using the following as junk.fsxops: truncate 0x0 0 0x927c0
write 0x63fb8 0x53c8 0 copy_range 0xb704 0x19b9 0x24429 0x79380 write 0x2402b 0x144a2 0x90660 * write
0x204d5 0x140a0 0x927c0 * copy_range 0x1f72c 0x137d0 0x7a906 0x927c0 * read 0x00000 0x20000 0x9157c read
0x20000 0x20000 0x9157c read 0x40000 0x20000 0x9157c read 0x60000 0x20000 0x9157c read 0x7e1a0 0xcfb9
0x9157c on cifs with the default cache option. It shows folio 0x24 misbehaving if the FMODE_READ check is
commented out in netfs_perform_write(): if (//(file->f_mode & FMODE_READ) || netfs_is_cache_enabled(ctx))
{ and no fscache. This was initially found with the generic/522 xfstest. (CVE-2026-64063)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19506.299.3 or later.

Plugin Details

Severity: High

ID: 469828

Version: Revision 1.6

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: High

Score: 7.6

Percentile: 98.35

Vendor

Vendor Severity: HIGH

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-2026-64063

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: 6/4/2026

Reference Information

CVE: CVE-2026-64063

Detections

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