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 20085.0.0

medium Tenable Cloud Security Plugin ID 470687

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: xsk: fix buffer leak in xsk_drop_skb()
for AF_XDP multi-buffer Tx This patch is inspired by the check[1] from sashiko. It says when overflow
happens, the address of cq to be published is invalid. Actually the severer thing is the whole process of
publishing the address of cq in this particular case is not right: it should truely publish the address
and advance the cached_prod in cq as long as it reads descriptors from txq. The following is the full
analysis. xsk_drop_skb() is called in three places, which all discard a partially built multi-buffer skb:
1) xsk_build_skb() -EOVERFLOW error path: packet exceeds MAX_SKB_FRAGS 2) __xsk_generic_xmit() post-loop
cleanup: an invalid descriptor in the TX ring prevents the partial packet from completing 3)
xsk_release(): socket close while xs->skb holds an incomplete packet In all three cases, the TX
descriptors for the already-processed frags have been consumed from the TX ring (xskq_cons_release), and
CQ slots have been reserved. However, xsk_drop_skb() calls xsk_consume_skb() which cancels the CQ
reservations via xsk_cq_cancel_locked(). Since the buffer addresses never appear in the completion queue,
userspace permanently loses track of these buffers. Fix this by letting consume_skb() trigger the existing
xsk_destruct_skb destructor, which already submits buffer addresses to the CQ via
xsk_cq_submit_addr_locked(). Note that cancelling the descriptors back to the TX ring (via
xskq_cons_cancel_n) is not a appropriate option because an oversized packet that always exceeds
MAX_SKB_FRAGS would be retried indefinitely, which is an obviously deadlock bug in the TX path. Also move
the desc->addr assignment in xsk_build_skb() above the overflow check so that the current descriptor's
address is recorded before a potential -EOVERFLOW jump to free_err, consistent with the zerocopy path in
xsk_build_skb_zerocopy(). [1]: https://lore.kernel.org/all/[email protected]/
(CVE-2026-74560)

Solution

Update the sys-kernel/cchost-kernel-6_18 library and its related packages to version 20085.0.0 or later.

Plugin Details

Severity: Medium

ID: 470687

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: 6.6

Temporal Score: 4.9

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

CVSS Score Source: CVE-2026-74560

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: 8/15/2026

Reference Information

CVE: CVE-2026-74560

Detections

Analytics