Google: sys-kernel/cchost-kernel-6_12, sys-kernel/csql-kernel-6_12, sys-kernel/lakitu-kernel-6_12, sys-kernel/lakitu-nc-kernel-6_12: security update to 19738.0.0

high Tenable Self-Hosted Container Security Plugin ID 470517

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: iommu/vt-d: Clear Present bit before
tearing down context entry When tearing down a context entry, the current implementation zeros the entire
128-bit entry using multiple 64-bit writes. This creates a window where the hardware can fetch a "torn"
entry — where some fields are already zeroed while the 'Present' bit is still set — leading to
unpredictable behavior or spurious faults. While x86 provides strong write ordering, the compiler may
reorder writes to the two 64-bit halves of the context entry. Even without compiler reordering, the
hardware fetch is not guaranteed to be atomic with respect to multiple CPU writes. Align with the
"Guidance to Software for Invalidations" in the VT-d spec (Section 6.5.3.3) by implementing the
recommended ownership handshake: 1. Clear only the 'Present' (P) bit of the context entry first to signal
the transition of ownership from hardware to software. 2. Use dma_wmb() to ensure the cleared bit is
visible to the IOMMU. 3. Perform the required cache and context-cache invalidation to ensure hardware no
longer has cached references to the entry. 4. Fully zero out the entry only after the invalidation is
complete. Also, add a dma_wmb() to context_set_present() to ensure the entry is fully initialized before
the 'Present' bit becomes visible. (CVE-2026-45944)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19738.0.0 or later.

Plugin Details

Severity: High

ID: 470517

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: 5

Percentile: 93.7

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 4.4

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

CVSS Score Source: CVE-2026-45944

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/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: 3/27/2026

Reference Information

CVE: CVE-2026-45944

Detections

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