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 20198.0.0

high Tenable Self-Hosted Container Security Plugin ID 475759

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: vxlan: reject dynamic fdb entries that
reference a nexthop id The commit cited in the Fixes tag allowed VXLAN FDB entries to point to FDB
nexthops so that overlay traffic could be load balanced across multiple VTEPs. Such entries can only be
configured from user space, cannot be learned and cannot roam. They only make sense with a user space
control plane such as E-VPN where data plane learning is disabled. Despite that, the VXLAN driver does not
currently prevent such entries from being configured with the "dynamic" flag. The per-nexthop FDB list is
only protected by the per-device hash lock, which is not sufficient when two VXLAN devices point to the
same FDB nexthop and therefore share the list. Aging runs in softirq context without RTNL, so an entry
deleted by one device can race with an addition or deletion from the other, leading to list corruption:
list_del corruption. next->prev should be ffff8881069d9548, but was dead000000000122.
(next=ffff8881069d9448) WARNING: CPU: 0 PID: 90 at lib/list_debug.c:65
__list_del_entry_valid_or_report+0x1aa/0x210 ... vxlan_fdb_destroy+0x5b8/0xad0 vxlan_cleanup+0x328/0x450
call_timer_fn+0x2a/0x1c0 run_timer_softirq+0x18c/0x210 BUG: KASAN: slab-use-after-free in
vxlan_fdb_destroy Fix this by rejecting the bogus configuration of dynamic FDB entries that point to FDB
nexthops, both when created and when an existing entry is updated. As such, the per-nexthop FDB list is
only ever mutated under the RTNL lock. Add test cases to make sure that this does not regress in the
future. (CVE-2026-98023)

Solution

Update the sys-kernel/cchost-kernel-6_18 library and its related packages to version 20198.0.0 or later.

Plugin Details

Severity: High

ID: 475759

Version: Revision 1.1

Type: Local

Family: Google COS Security Checks

Published: 10/16/2026

Updated: 10/16/2026

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.34

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-2026-98023

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: 9/25/2026

Reference Information

CVE: CVE-2026-98023

Detections

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