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 19506.224.36

medium Tenable Self-Hosted Container Security Plugin ID 469848

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: af_unix: Give up GC if MSG_PEEK
intervened. Igor Ushakov reported that GC purged the receive queue of an alive socket due to a race with
MSG_PEEK with a nice repro. This is the exact same issue previously fixed by commit cbcf01128d0a
("af_unix: fix garbage collect vs MSG_PEEK"). After GC was replaced with the current algorithm, the cited
commit removed the locking dance in unix_peek_fds() and reintroduced the same issue. The problem is that
MSG_PEEK bumps a file refcount without interacting with GC. Consider an SCC containing sk-A and sk-B,
where sk-A is close()d but can be recv()ed via sk-B. The bad thing happens if sk-A is recv()ed with
MSG_PEEK from sk-B and sk-B is close()d while GC is checking unix_vertex_dead() for sk-A and sk-B. GC
thread User thread --------- ----------- unix_vertex_dead(sk-A) -> true <------. \ `------ recv(sk-B,
MSG_PEEK) invalidate !! -> sk-A's file refcount : 1 -> 2 close(sk-B) -> sk-B's file refcount : 2 -> 1
unix_vertex_dead(sk-B) -> true Initially, sk-A's file refcount is 1 by the inflight fd in sk-B recvq. GC
thinks sk-A is dead because the file refcount is the same as the number of its inflight fds. However,
sk-A's file refcount is bumped silently by MSG_PEEK, which invalidates the previous evaluation. At this
moment, sk-B's file refcount is 2; one by the open fd, and one by the inflight fd in sk-A. The subsequent
close() releases one refcount by the former. Finally, GC incorrectly concludes that both sk-A and sk-B are
dead. One option is to restore the locking dance in unix_peek_fds(), but we can resolve this more
elegantly thanks to the new algorithm. The point is that the issue does not occur without the subsequent
close() and we actually do not need to synchronise MSG_PEEK with the dead SCC detection. When the issue
occurs, close() and GC touch the same file refcount. If GC sees the refcount being decremented by close(),
it can just give up garbage-collecting the SCC. Therefore, we only need to signal the race during MSG_PEEK
with a proper memory barrier to make it visible to the GC. Let's use seqcount_t to notify GC when MSG_PEEK
occurs and let it defer the SCC to the next run. This way no locking is needed on the MSG_PEEK side, and
we can avoid imposing a penalty on every MSG_PEEK unnecessarily. Note that we can retry within
unix_scc_dead() if MSG_PEEK is detected, but we do not do so to avoid hung task splat from abusive
MSG_PEEK calls. (CVE-2026-23394)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19506.224.36 or later.

Plugin Details

Severity: Medium

ID: 469848

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: Low

Score: 3

Percentile: 23.65

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Low

Base Score: 3.8

Temporal Score: 2.8

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

CVSS Score Source: CVE-2026-23394

CVSS v3

Risk Factor: Medium

Base Score: 4.7

Temporal Score: 4.1

Vector: CVSS:3.0/AV:L/AC:H/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: 3/25/2026

Reference Information

CVE: CVE-2026-23394

Detections

Analytics