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 19999.44.106

high Tenable Cloud Security Plugin ID 475315

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: RDMA/ucma: Lock the handler in
ucma_write_cm_event() ctx->file may only be changed under the handler lock and the xa_lock, which is what
stops uevents being queued for a ctx while ucma_migrate_id() moves it to another file. The CM core takes
that lock before invoking ucma_event_handler(), but the write() paths that queue uevents themselves do
not. ucma_write_cm_event() re-reads ctx->file for each of its four dereferences, so ucma_migrate_id() can
swap it mid-sequence: mutex_lock(&ctx->file->mut); /* file A */ list_add_tail(&uevent->list,
&ctx->file->event_list); /* file B */ mutex_unlock(&ctx->file->mut); /* file B */
wake_up_interruptible(&ctx->file->poll_wait); /* file B */ The window is the mutex_lock() itself: the
writer sleeps in it while the migration reassigns ctx->file. The list_add_tail() then runs on file B's
event_list holding only file A's mutex: list_add corruption. prev->next should be next (ffff888101320f30),
but was ffff88814a08c418. (prev=ffff88814a075c18). kernel BUG at lib/list_debug.c:32! Call Trace:
ucma_write_cm_event+0x36e/0x5e0 and file A's mut is left held forever, wedging its next writer in D state.
The uevent is also stranded on a list ucma_cleanup_ctx_events() will not walk, so it outlives its context.
/dev/infiniband/rdma_cm is 0666 and no RDMA device is involved, so an unprivileged user reaches all of
this. Take the handler lock, as ucma_cleanup_mc_events() does; ctx->cm_id is pinned by the ucma_get_ctx()
reference. (CVE-2026-89507)

Solution

Update the sys-kernel/cchost-kernel-6_18 library and its related packages to version 19999.44.106 or later.

Plugin Details

Severity: High

ID: 475315

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: 58.28

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2026-89507

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/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-2026-89507

Detections

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