Google: sys-kernel/cchost-kernel-6_12, sys-kernel/cchost-kernel-6_18, sys-kernel/csql-kernel-6_12, sys-kernel/csql-kernel-6_18, sys-kernel/lakitu-kernel-6_12, sys-kernel/lakitu-kernel-6_18, sys-kernel/lakitu-nc-kernel-6_12, sys-kernel/lakitu-nc-kernel-6_18: security update to 19862.0.0

critical Tenable Cloud Security Plugin ID 470043

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: tcp: fix stale per-CPU tcp_tw_isn leak
enabling ISN prediction Blamed commit moved the TIME_WAIT-derived ISN from the skb control block to a per-
CPU variable, assuming the value would always be consumed by tcp_conn_request() for the same packet that
wrote it. That assumption is violated by multiple drop paths between the producer
(__this_cpu_write(tcp_tw_isn, isn) in tcp_v{4,6}_rcv()) and the consumer (tcp_conn_request()): - min_ttl /
min_hopcount check - xfrm policy check - tcp_inbound_hash() MD5/AO mismatch - tcp_filter()
eBPF/SO_ATTACH_FILTER drop - th->syn && th->fin discard in tcp_rcv_state_process() TCP_LISTEN -
psp_sk_rx_policy_check() in tcp_v{4,6}_do_rcv() - tcp_checksum_complete() in tcp_v{4,6}_do_rcv() -
tcp_v{4,6}_cookie_check() returning NULL When a packet is dropped on any of these paths, tcp_tw_isn is
left set. The next SYN processed on the same CPU then consumes the non zero value in tcp_conn_request(),
receiving a potentially predictable ISN. This patch moves back tcp_tw_isn to skb->cb[], getting rid of the
per-cpu variable. Note that tcp_v{4,6}_fill_cb() do not set it. Very litle impact on overall code
size/complexity: $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/0 grow/shrink: 2/1
up/down: 8/-15 (-7) Function old new delta tcp_v6_rcv 3038 3042 +4 tcp_v4_rcv 3035 3039 +4
tcp_conn_request 2938 2923 -15 Total: Before=24436060, After=24436053, chg -0.00% (CVE-2026-64024)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19862.0.0 or later.

Plugin Details

Severity: Critical

ID: 470043

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: Medium

Score: 4.5

Percentile: 57.61

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: High

Base Score: 9.7

Temporal Score: 7.2

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:C/A:C

CVSS Score Source: CVE-2026-64024

CVSS v3

Risk Factor: Critical

Base Score: 9.4

Temporal Score: 8.2

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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: 6/22/2026

Reference Information

CVE: CVE-2026-64024

Detections

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