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 19999.44.28

medium Tenable Self-Hosted Container Security Plugin ID 471087

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: futex: Prevent robust futex exit race
some more A robust futex unlock stores 0 over the whole futex value - wiping FUTEX_WAITERS - and wakes a
single waiter. That wakeup is a one-shot notification: the protocol relies on its recipient to either
acquire the futex (and eventually unlock while aware of the remaining contention) or re-arm FUTEX_WAITERS
before sleeping again. If the woken waiter is killed before it can do either, the kernel must jump in and
wake the next task down the line. This is a known complication of the futex protocol with a previous
partial fix in commit ca16d5bee598 ("futex: Prevent robust futex exit race"). Unfortunately, that fix is
insufficient. If a third task re-acquired the futex through the uncontended fast path in the meantime, the
notification is lost: robust exit processing sees that it is owned by another task and does nothing, while
the new owner sees no FUTEX_WAITERS when it unlocks and wakes nobody. The remaining waiters sleep forever
behind a free futex: A owns the futex, B and C sleep in FUTEX_WAIT uval == A | FUTEX_WAITERS A robust
unlock: store 0, FUTEX_WAKE(1) wakes B uval == 0 D fast path acquire: cmpxchg(0 -> D) uval == D, no
FUTEX_WAITERS B killed before acting on the wakeup B exit walk, pending op: owner D != B -> no action D
unlock: no FUTEX_WAITERS -> no wake C sleeps forever This is clearly a shortcoming in the implementation,
which fails to keep the FUTEX_WAITERS bit consistent. Work around this by augmenting the robust list exit
processing to also perform the extra wakeup if the futex word is owned by another thread but FUTEX_WAITERS
is not set. This does not fix the problem of a non-contended take over/release and free sequence, which
has been discussed for years and has been addressed by commit 3ca9595d9fb6 ("futex: Add support for
unlocking robust futexes") and subsequent changes, but failed to take the problem described above into
account. A more complete solution which is based on the in kernel unlock of contended robust futexes has
been discussed in the context of this change and should show up in mainline sooner than later. [ tglx:
Amend change log slightly and fixup coding style ] (CVE-2026-74658)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19999.44.28 or later.

Plugin Details

Severity: Medium

ID: 471087

Version: Revision 1.3

Type: Local

Family: Google COS Security Checks

Published: 10/3/2026

Updated: 10/3/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Medium

Score: 5.7

Percentile: 96.05

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

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

CVSS Score Source: CVE-2026-74658

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: 8/22/2026

Reference Information

CVE: CVE-2026-74658

Detections

Analytics