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 20162.0.0

medium Tenable Cloud Security Plugin ID 475754

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: bpf: Fix infinite loop in
pcpu_freelist push with one possible CPU __pcpu_freelist_push() can loop forever when only one CPU is
possible and an NMI re-enters pcpu_freelist_push() while the interrupted context holds that CPU's freelist
lock. After the current-CPU fast path fails, the fallback loop walks cpu_possible_mask while skipping the
current CPU. With CONFIG_SMP=n, or when an SMP kernel is limited to one possible CPU with nr_cpus=1 or
possible_cpus=1, there are no other possible CPUs to examine. The loop therefore makes no lock acquisition
attempt and can never make progress. The following stack was observed on a UP system: NMI context:
pcpu_freelist_push free_htab_elem htab_map_delete_elem [perf-event BPF program] __perf_event_overflow
perf_event_nmi_handler exc_nmi Interrupted context: __pcpu_freelist_push pcpu_freelist_push free_htab_elem
htab_map_delete_elem [raw_tp/sys_enter BPF program] __bpf_trace_sys_enter do_syscall_64
raw_res_spin_lock() detects the same-CPU recursive acquisition and returns -EDEADLK, but the subsequent
fallback loop has no candidate head on a system with one possible CPU. Restore the extra fallback head
that existed before the rqspinlock conversion. Keep the current-CPU fast path, then try the other possible
CPUs and finally the extra head. The additional head lets a push, which cannot fail without losing a
preallocated element, make progress when the only per-CPU head is held by the interrupted context. Also
check the extra head from the pop path so that nodes placed there can be reused. (CVE-2026-89991)

Solution

Update the sys-kernel/cchost-kernel-6_18 library and its related packages to version 20162.0.0 or later.

Plugin Details

Severity: Medium

ID: 475754

Version: Revision 1.1

Type: Local

Family: Google COS Security Checks

Published: 10/16/2026

Updated: 10/16/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.61

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 3.6

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

CVSS Score Source: CVE-2026-89991

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: 9/16/2026

Reference Information

CVE: CVE-2026-89991

Detections

Analytics