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

critical Tenable Self-Hosted Container Security Plugin ID 475779

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: svcrdma: Fix offset arithmetic in
read_chunk_range svc_rdma_read_chunk_range() walks a Read chunk's segment list to build a sub-range
starting at byte offset and spanning length bytes for a Position-Zero or Call chunk. Two arithmetic
defects in the per-segment loop produce wrong DMA lengths and a u32 underflow:
pcl_for_each_segment(segment, chunk) { if (offset > segment->rs_length) { offset -= segment->rs_length;
continue; } dummy.rs_handle = segment->rs_handle; dummy.rs_length = min_t(u32, length, segment->rs_length)
- offset; dummy.rs_offset = segment->rs_offset + offset; First, the skip predicate uses '>' instead of
'>='. When offset equals the segment's full rs_length, the segment is fully consumed and should be
skipped, but the loop falls through into the body. The resulting dummy.rs_length is min_t(u32, length,
rs_length) - rs_length, which underflows to a near-UINT_MAX u32 when length is smaller than rs_length, or
is zero otherwise. Second, the length formula subtracts offset from the min_t() result rather than from
segment->rs_length before the cap. For offset > 0 the segment's residual is rs_length - offset, not
rs_length, so the cap must be applied to the residual. With the current bracketing, whenever length is
smaller than rs_length - offset the per-segment length becomes length - offset instead of length, silently
dropping offset bytes from the rebuilt chunk. Combined with the boundary case above it also enables the
u32 underflow path, which propagates a huge nr_bvec into svc_rdma_build_read_segment() and a multi-MiB
kmalloc_array_node() in svc_rdma_get_rw_ctxt(). Additionally, svc_rdma_read_call_chunk() can invoke this
function with length == 0 when the last Read chunk ends exactly at the end of the Call chunk. With the
corrected >= predicate, every segment is skipped and the function returns the initial -EINVAL, rejecting a
valid request. Return success immediately when length is zero. Also break out of the loop once length is
fully consumed to avoid passing zero-length segments to svc_rdma_build_read_segment(). Fix by using '>='
so a fully-consumed segment is skipped, by moving '- offset' inside min_t() so the cap is applied to the
segment's residual length, by returning success for zero-length requests, and by stopping iteration when
the requested range has been consumed. (CVE-2026-89533)

Solution

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

Plugin Details

Severity: Critical

ID: 475779

Version: Revision 1.1

Type: Local

Family: Google COS Security Checks

Published: 10/16/2026

Updated: 10/16/2026

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.39

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-89533

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/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: 9/11/2026

Reference Information

CVE: CVE-2026-89533

Detections

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