Google: sys-kernel/cchost-kernel-6_18, sys-kernel/csql-kernel-6_18, sys-kernel/lakitu-kernel-6_18, sys-kernel/lakitu-nc-kernel-6_18: security update to 19804.0.0

medium Tenable Cloud Security Plugin ID 470680

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: bridge: guard local VLAN-0 FDB helpers
against NULL vlan group When CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and nbp_vlan_group()
return NULL (br_private.h stub definitions). The BR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled
unconditionally and reaches br_fdb_delete_locals_per_vlan_port() and br_fdb_insert_locals_per_vlan_port(),
where the NULL vlan group pointer is dereferenced via list_for_each_entry(v, &vg->vlan_list, vlist). The
observed crash is in the delete path, triggered when creating a bridge with IFLA_BR_MULTI_BOOLOPT
containing BR_BOOLOPT_FDB_LOCAL_VLAN_0 via RTM_NEWLINK. The insert helper has the same bug pattern. Oops:
general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI
KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7] RIP:
0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310 Call Trace: br_fdb_toggle_local_vlan_0+0x452/0x4c0
br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276 br_boolopt_toggle net/bridge/br.c:313
br_boolopt_multi_toggle net/bridge/br.c:364 br_changelink net/bridge/br_netlink.c:1542 br_dev_newlink
net/bridge/br_netlink.c:1575 Add NULL checks for the vlan group pointer in both helpers, returning early
when there are no VLANs to iterate. This matches the existing pattern used by other bridge FDB functions
such as br_fdb_add() and br_fdb_delete(). (CVE-2026-43100)

Solution

Update the sys-kernel/cchost-kernel-6_18 library and its related packages to version 19804.0.0 or later.

Plugin Details

Severity: Medium

ID: 470680

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: Low

Score: 3

Percentile: 23.67

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-2026-43100

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: 5/6/2026

Reference Information

CVE: CVE-2026-43100

Detections

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